Low-Level Notebook Structure

Like everything else in the Wolfram Language, notebooks are ultimately symbolic expressions. When you edit notebooks—or apply high-level programmatic functions—the Wolfram Language automatically updates these expressions. But if you look at the lowest level—say by opening a notebook file as text—you will see the underlying expressions, in which formatting constructs are represented as a hierarchy of low-level symbolic "boxes".

(Key2[ctrl, shift, e]) — toggle between formatted display and underlying symbolic expression

(RefLink[Notebook, paclet:ref/Notebook]) — low-level symbolic representation for a notebook

(RefLink[Cell, paclet:ref/Cell]) — low-level representation for a cell in a notebook

(RefLink[RowBox, paclet:ref/RowBox]) — low-level representation for a row of arbitrary elements

(RefLink[GridBox, paclet:ref/GridBox]) — low-level representation of an arbitrary 2D layout

(RefLink[StyleBox, paclet:ref/StyleBox]) — low-level wrapper specifying styles and style options to apply