Sometimes it's hard to find the right man page for a given topic. In that case, you might try using man -k to search the NAME section of the man pages. Be warned that it's a substring search, so running something like man -k ls will give you a lot of output! Here's an example using a more specific query:

$ man -k whatis
apropos              (1)  - search the whatis database for strings
makewhatis           (8)  - Create the whatis database
whatis               (1)  - search the whatis database for complete words