Document Structure¶

Topic: LaTeX Lesson: 2 of 16 Prerequisites: Lesson 1 (Introduction and Setup) Objective: Master document classes, preamble configuration, sectioning commands, and techniques for organizing complex documents

Document Classes¶

Every LaTeX document begins with \documentclass{...}. The document class defines the overall structure and formatting rules for your document.

Standard Document Classes¶

LaTeX provides several built-in document classes:

article¶

Purpose: Short documents without chapters (papers, articles, reports)

Characteristics: - No \chapter command - Starts with \section as top-level division - Abstract environment available - Typically single-sided

Example:

\documentclass{article}

\title{A Brief Study on LaTeX}
\author{Jane Doe}
\date{February 2024}

\begin{document}
\maketitle

\begin{abstract}
This paper explores the fundamentals of LaTeX document preparation.
\end{abstract}

\section{Introduction}
LaTeX is a powerful typesetting system...

\end{document}

report¶

Purpose: Longer documents with chapters (technical reports, theses)

Characteristics: - Includes \chapter command - Chapters start on new pages - Default is single-sided - Title page separate from abstract

Example:

\documentclass{report}

\title{Annual Technical Report}
\author{Engineering Team}
\date{2024}

\begin{document}
\maketitle

\begin{abstract}
This report summarizes our technical achievements in 2024.
\end{abstract}

\tableofcontents

\chapter{Introduction}
This report covers...

\chapter{Methodology}
Our approach was...

\end{document}

book¶

Purpose: Books and long documents

Characteristics: - Designed for two-sided printing - Includes \chapter, \frontmatter, \mainmatter, \backmatter - Chapters can start on right-hand pages only - Separate formatting for front matter (roman numerals for pages)

Example:

\documentclass{book}

\title{Introduction to Quantum Computing}
\author{Dr. Smith}
\date{2024}

\begin{document}

\frontmatter
\maketitle
\tableofcontents

\mainmatter
\chapter{Quantum Mechanics Basics}
Before diving into quantum computing...

\chapter{Quantum Gates}
Quantum gates are...

\backmatter
\chapter{Appendix}
Additional reference material...

\end{document}

letter¶

Purpose: Business and formal letters

Characteristics: - Special letter formatting - Address blocks - Signature lines

Example:

\documentclass{letter}

\signature{John Smith}
\address{123 Main St \\ Anytown, USA}

\begin{document}

\begin{letter}{Ms. Jane Doe \\ Director of Research \\ University of Excellence}

\opening{Dear Ms. Doe,}

I am writing to express my interest in the research position...

\closing{Sincerely,}

\end{letter}

\end{document}

Document Class Options¶

Options are specified in square brackets: \documentclass[options]{class}

Font Size¶

Available sizes: 10pt (default), 11pt, 12pt

\documentclass[12pt]{article}  % Larger, easier to read

Paper Size¶

Common options: - letterpaper (default in US, 8.5" × 11") - a4paper (international standard, 210mm × 297mm) - a5paper, b5paper, legalpaper, executivepaper

\documentclass[a4paper]{article}

Layout¶

Two-sided vs. One-sided: - oneside (default for article/report) - twoside (default for book)

\documentclass[twoside]{article}

Column Layout: - onecolumn (default) - twocolumn

\documentclass[twocolumn]{article}

Title Page¶

titlepage: Title on separate page
notitlepage: Title at top of first page (default for article)

\documentclass[titlepage]{article}

Equations¶

leqno: Equation numbers on left
fleqn: Left-aligned equations (instead of centered)

\documentclass[leqno]{article}

Combining Options¶

Multiple options are comma-separated:

\documentclass[12pt, a4paper, twoside, titlepage]{article}

The Preamble¶

Everything between \documentclass and \begin{document} is the preamble. This is where you: - Load packages - Define custom commands - Set document metadata - Configure document-wide settings

Loading Packages¶

Packages extend LaTeX functionality. Load them with \usepackage[options]{package}.

Essential Packages:

% Encoding and fonts
\usepackage[utf8]{inputenc}      % UTF-8 input encoding
\usepackage[T1]{fontenc}         % Modern font encoding
\usepackage{lmodern}             % Latin Modern fonts

% Language and typography
\usepackage[english]{babel}      % Language-specific rules
\usepackage{microtype}           % Improved typography

% Mathematics
\usepackage{amsmath}             % Enhanced math environments
\usepackage{amssymb}             % Additional math symbols
\usepackage{amsthm}              % Theorem environments

% Graphics and colors
\usepackage{graphicx}            % Include images
\usepackage{xcolor}              % Color support

% Hyperlinks
\usepackage{hyperref}            % Clickable links (load last!)

% Page layout
\usepackage{geometry}            % Customize margins
\geometry{margin=1in}

Common Packages by Category:

Category	Package	Purpose
Math	`amsmath`, `amssymb`, `mathtools`	Enhanced mathematical typesetting
Figures	`graphicx`, `subfig`, `caption`	Include and manage images
Tables	`booktabs`, `array`, `longtable`	Professional tables
Code	`listings`, `minted`, `verbatim`	Display source code
References	`biblatex`, `natbib`, `hyperref`	Bibliography and hyperlinks
Layout	`geometry`, `fancyhdr`, `multicol`	Page layout control

Document Metadata¶

Define document information in the preamble:

\title{The Document Title}
\author{First Author \and Second Author}
\date{March 2024}
% Or use \date{\today} for automatic date
% Or use \date{} for no date

For multiple authors with affiliations:

\title{Research Paper Title}
\author{
    John Smith\thanks{Department of Physics, University A} \and
    Jane Doe\thanks{Department of Mathematics, University B}
}
\date{\today}

Custom Commands¶

Define shortcuts and custom commands in the preamble:

% Simple text substitution
\newcommand{\latex}{\LaTeX}
\newcommand{\tex}{\TeX}

% Commands with arguments
\newcommand{\abs}[1]{\left| #1 \right|}
\newcommand{\norm}[1]{\left\| #1 \right\|}

% Math operators
\DeclareMathOperator{\trace}{Tr}
\DeclareMathOperator{\rank}{rank}

Usage:

The absolute value is $\abs{x}$, and the trace is $\trace(A)$.

Document Body¶

The actual content goes between \begin{document} and \end{document}.

Title Generation¶

Generate the title block with \maketitle:

\begin{document}

\maketitle  % Creates title using \title, \author, \date from preamble

\end{document}

Abstract¶

For academic papers (article/report classes):

\begin{document}

\maketitle

\begin{abstract}
This paper investigates the fundamental properties of LaTeX document
preparation systems. We demonstrate that proper structure leads to
high-quality typesetting.
\end{abstract}

\section{Introduction}
...

\end{document}

Table of Contents¶

Automatically generate a table of contents:

\tableofcontents

Important: Requires two compilation passes: 1. First pass: Writes section information to .toc file 2. Second pass: Reads .toc and generates TOC

Customization:

% Control depth (default is 3 for article)
\setcounter{tocdepth}{2}  % Only show sections and subsections

% Control section numbering depth
\setcounter{secnumdepth}{2}  % Only number up to subsections

Lists of Figures and Tables¶

\listoffigures  % List of figures
\listoftables   % List of tables

These also require multiple compilation passes and rely on \caption commands in figures/tables.

Sectioning Commands¶

LaTeX provides hierarchical sectioning commands with automatic numbering.

Article Class Hierarchy¶

\section{Section Title}
\subsection{Subsection Title}
\subsubsection{Subsubsection Title}
\paragraph{Paragraph Title}
\subparagraph{Subparagraph Title}

Example:

\section{Introduction}
This is the introduction.

\subsection{Background}
Some background information.

\subsubsection{Historical Context}
Historical details.

\paragraph{Early Developments}
The early period was characterized by...

\subparagraph{Key Figures}
Important contributors included...

Output numbering:

1 Introduction
1.1 Background
1.1.1 Historical Context
Early Developments. The early period...
Key Figures. Important contributors...

Report/Book Class Hierarchy¶

\chapter{Chapter Title}
\section{Section Title}
\subsection{Subsection Title}
% ... same as article below this level

Example:

\chapter{Quantum Mechanics}

\section{Wave Functions}
The wave function describes...

\subsection{Normalization}
Wave functions must be normalized...

Unnumbered Sections¶

Add * to suppress numbering (also excludes from TOC):

\section*{Acknowledgments}
We thank the reviewers for their helpful comments.

\subsection*{Funding}
This work was supported by...

To include in TOC without numbering:

\section*{Acknowledgments}
\addcontentsline{toc}{section}{Acknowledgments}

Appendices¶

Switch to appendix mode:

\appendix

\section{Derivation of Key Formula}
Detailed mathematical derivation...

\section{Supplementary Data}
Additional experimental results...

In appendix mode, sections are numbered A, B, C instead of 1, 2, 3.

For books:

\appendix

\chapter{Mathematical Proofs}
\section{Proof of Theorem 1}
...

Custom Section Titles¶

Control how sections appear in TOC vs. in text:

\section[Short Title for TOC]{Very Long Title That Appears in the Document}

Document Structure Best Practices¶

Complete Article Example¶

\documentclass[12pt, a4paper]{article}

% Packages
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsmath, amssymb}
\usepackage{graphicx}
\usepackage{hyperref}

% Metadata
\title{The Art of Structured Documents}
\author{Jane Smith}
\date{\today}

% Custom commands
\newcommand{\latex}{\LaTeX}

\begin{document}

% Front matter
\maketitle

\begin{abstract}
We present a study on document structure in \latex{}.
\end{abstract}

\tableofcontents
\newpage

% Main content
\section{Introduction}
Document structure is crucial for readability.

\subsection{Motivation}
Well-structured documents are easier to navigate.

\section{Methodology}
We analyzed 100 \latex{} documents.

\subsection{Data Collection}
Documents were collected from academic repositories.

\subsection{Analysis}
Statistical analysis was performed.

\section{Results}
Structured documents showed 40\% better readability.

\section{Conclusion}
Proper structure matters.

% References (would use BibTeX normally)
\begin{thebibliography}{9}
\bibitem{knuth}
Donald Knuth. \textit{The TeXbook}, 1984.
\end{thebibliography}

\end{document}

Complete Report Example¶

\documentclass[12pt, a4paper]{report}

\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\usepackage{graphicx}
\usepackage{hyperref}

\title{Annual Progress Report}
\author{Research Team}
\date{2024}

\begin{document}

\maketitle

\begin{abstract}
This report summarizes our achievements in 2024.
\end{abstract}

\tableofcontents
\listoffigures
\listoftables

\chapter{Introduction}
This report covers our research activities.

\section{Project Overview}
Our project focuses on...

\section{Team Members}
The team consists of...

\chapter{Research Activities}

\section{Theoretical Work}
We developed new models for...

\section{Experimental Work}
Laboratory experiments were conducted...

\chapter{Publications}
We published 5 papers this year.

\chapter{Conclusions and Future Work}

\section{Summary}
We made significant progress.

\section{Future Directions}
Next year we plan to...

\appendix

\chapter{Detailed Experimental Data}
Raw data tables are provided here.

\end{document}

Comments¶

Comments are ignored during compilation:

% This is a single-line comment

This text is visible. % This comment is invisible

% You can comment out code temporarily:
% \section{Work in Progress}
% This section is not compiled yet.

Multi-line comments require the verbatim package:

\usepackage{verbatim}

\begin{comment}
This entire block
is commented out
no matter how many lines
\end{comment}

Basic Document Commands¶

Line and Page Breaks¶

Line breaks:

This is line one. \\
This is line two.

% Or with added vertical space:
This is line one. \\[1cm]
This is line two with 1cm extra space above.

Page breaks:

\newpage           % Start a new page
\clearpage         % Start new page and flush floats (figures/tables)
\pagebreak         % Suggest page break (LaTeX decides)
\nopagebreak       % Discourage page break

Horizontal and Vertical Space¶

% Horizontal space
Word1\hspace{1cm}Word2          % 1cm horizontal space
Word1\hfill Word2               % Fill all available space

% Vertical space
Text before.
\vspace{2cm}
Text after.

% Stretchy space
\vfill  % Fill vertical space (useful for title pages)

Input and Include¶

For large documents, split content across multiple files.

\input{filename}¶

Behavior: Inserts content as if it were typed directly at that location.

Main file (main.tex):

\documentclass{article}

\title{Multi-File Document}
\author{Author Name}

\begin{document}
\maketitle

\input{introduction}
\input{methodology}
\input{results}
\input{conclusion}

\end{document}

Separate file (introduction.tex):

\section{Introduction}
This is the introduction section.

Note: No \documentclass or \begin{document} in included files.

\include{filename}¶

Behavior: - Issues \clearpage before and after - Creates separate .aux file - Can be used with \includeonly for selective compilation

Usage:

% In preamble
\includeonly{chapter1,chapter3}  % Only compile these

\begin{document}

\include{chapter1}
\include{chapter2}  % Skipped
\include{chapter3}
\include{chapter4}  % Skipped

\end{document}

When to use each: - \input: Small sections, doesn't force page break - \include: Chapters, large sections, when you want selective compilation

Nested Inputs¶

You can nest \input commands:

main.tex:

\input{chapter1}

chapter1.tex:

\section{Chapter 1}
\input{chapter1/section1}
\input{chapter1/section2}

Directory Structure for Large Documents¶

Recommended organization:

thesis/
├── main.tex
├── preamble.tex
├── chapters/
│   ├── chapter1.tex
│   ├── chapter2.tex
│   └── chapter3.tex
├── figures/
│   ├── graph1.pdf
│   └── diagram2.png
├── tables/
│   └── results.tex
└── bibliography.bib

main.tex:

\documentclass{report}

\input{preamble}  % All packages and settings

\begin{document}

\input{chapters/chapter1}
\input{chapters/chapter2}
\input{chapters/chapter3}

\bibliographystyle{plain}
\bibliography{bibliography}

\end{document}

Exercises¶

Exercise 1: Document Classes¶

Create three separate documents: 1. An article with sections and subsections 2. A report with chapters and sections 3. A book with front matter, main matter, and back matter

Exercise 2: Table of Contents¶

Create an article with: - At least 3 sections - At least 2 subsections per section - A table of contents - Compile twice and observe the .toc file

Exercise 3: Options Exploration¶

Create the same document with these different option combinations: - [10pt, letterpaper, oneside] - [12pt, a4paper, twoside] - [11pt, a4paper, twocolumn]

Compare the output PDFs.

Exercise 4: Unnumbered Sections¶

Create a document with: - Regular numbered sections - An unnumbered "Acknowledgments" section - An unnumbered "References" section - Both unnumbered sections appear in the TOC

Exercise 5: Multi-File Document¶

Create a project with: - main.tex (main file) - intro.tex (introduction section) - methods.tex (methods section) - conclusion.tex (conclusion section)

Use \input{} to combine them.

Exercise 6: Custom Commands¶

Define and use these custom commands: - \R for the real numbers symbol $\mathbb{R}$ - \dd for differential operator (e.g., \dd x → dx) - \vect[1]{...} for bold vectors

Exercise 7: Complete Report¶

Create a technical report with: - Title page - Abstract - Table of contents - 3 chapters - Appendix with supplementary material - Bibliography (use thebibliography environment)

Summary¶

In this lesson, you learned:

Document classes: article, report, book, letter and their characteristics
Class options: Font size, paper size, layout options
Preamble: Loading packages, setting metadata, defining custom commands
Document body: Title generation, abstracts, tables of contents
Sectioning: Hierarchical structure from chapters to subparagraphs
Appendices: Creating supplementary sections
Comments: Single and multi-line commenting
File organization: Using \input{} and \include{} for large documents

These foundational concepts will be used in every LaTeX document you create. Next, we'll explore text formatting—fonts, colors, lists, and special characters.

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