Naturally, this can be only the briefest of guides. The best way to learn what philosophy is, is to do some. Be that as it may, the following document, Philosophy: A Brief Guide for Undergraduates by Robert Audi, gives a very clear overview of and introduction to the subject. It contains the following sections:
We are grateful to the American Philosophical Association for permission to reproduce this document. Contained in the guide are also links to a Map of the Major Branches of Philosophy, a Chronological Map of the Great Philosophers, and Peter Milne's What is logic and why do philosophers study it?.
Recommending introductory texts is always difficult: the best introduction to philosophy is philosophy itself, and introductory texts too often fail to exemplify what they are supposed to be introducing you to. Nevertheless, the current author will throw caution to the wind and unhesitatingly recommend: