Each new chapter in a book introduces a new epoch, a change of scene, a different set of actors, the beginning or end of a thread. In the same way, formal writing is anchored on a logical and coherent structure. These are called sections.

Each section explores one of the themes--set out earlier--in greater detail. The heading of the section aids the eye to focus quickly on the subject matter of interest. Sections are pillars of a coherent and cogent document structure. Sub-sections, similarly, focus on the sub-theses or main points set out in the section.

Sectioning is called by a command \section{}. The heading of the section is provided within the curly braces. The sections are by default numbered, although one can change the numbering scheme. The numbering scheme can be suppressed by adding a star: \section*{}.

The code snippet below produces the Figure 4.2

Figure 4.2 Sections and sub-sections