<\body> The provides call-back macros which allow page headers and footers to change automatically when specifying the title information of the document or when starting a new section. <\explain|> This macro is called when specifying the of a document. <\explain|> This macro is called when specifying the (s) of a document. <\explain|> This macro is called at the start of each new primary section ( for book style, or for article style). The is a literal text like ``Chapter'' or ``Section''. <\explain|> This macro is called at the start of each new secondary section ( for book style, or for article style). The is a literal text like ``Section'' or ``Paragraph''. In style files, page headers and footers are usually set by the above call-back macros, and not manually. You may directly modify headers and footers by setting the or using several supplied by .