Styled Notebook opens the Stylesheets palette to create a styled notebook.

ClearSystemCache[] clears internal system caches of stored results.

DisplayEndPacket[] is a MathLink packet that indicates the end of a series of expressions relating to a postscript graphic.

DisplayPacket[] is a MathLink packet that indicates the beginning of a series of expressions related to a PostScript graphic.

LineSpacing is an option for Style and Cell that specifies the spacing between successive lines of text.

NotebookAutoSave is a notebook option which specifies whether the notebook should automatically be saved after each piece of output generated by evaluation in it.

ParentDirectory[] gives the parent of the current working directory. ParentDirectory["dir"] gives the parent of the directory dir.

Cells as Mathematica Expressions Notebooks as Mathematica Expressions Manipulating Notebooks from the Kernel

MassIndex

Automatic Grouping automatically creates hierarchical cell groups on the basis of cell style.