This declaration
corresponds to the center environment. This
declaration can be used inside an environment such as quote or in a
parbox. The text of a figure or table can be centered on the page by
putting a \centering command at the beginning of the figure or table
environment.
Unlike the center environment,
the \centering command does not start
a new paragraph; it simply changes how LaTeX formats paragraph units.
To affect a paragraph unit's format, the scope of the declaration
must contain the blank line or \end command (of an environment like
quote) that ends the paragraph unit.
Editor's note: although not listed as fragile
in Lamport, I have found it necessary to use a \protect when putting
a \centering command in a
sectioning command.
For example,