Cats For Dummies
, P. 138/9, Chapter 9, "Good Grooming:"
"Why Cats Groom:
...Scent-Marking: Grooming helps to distribute a cat's scent across his whole body, a phenonmenon very reassuring to this scent-oriented animal. Scent is so important that a cat often licks himself right after being petted, both to re-establish his own scent and to drink in yours.
...Sociality: In a multicat household, especially one with littermates, you often see cats grooming each other. This behavior - which is also performed on beloved humans - is a way of reinforcing a cat's connection to his family.
...Changes in the condition of your cat's coat or grooming behavior may be a sign of illness..."
Our kitties completely groom themselves after the weekly bath (I'm allergic to cats, so they get bathed weekly). It takes them hours. But boy are they soft and shiny after the process!!!