This isn't really a book that you read, although if you're a pilot, you sure as hell better be familiar with the stuff that applies to you in the FAR section, because it's the law.

The FAR/AIM consists of two sections, the FAR (Federal Aviation Regulations) which is the legal framework within which pilots operate within the National Airspace System in the US. This version contains those laws most pertinent to pilots (there are other versions of this book for maintenance workers and flight crew). If you've passed an FAA knowledge test, chances are good that you know a lot of the stuff that's in here, whether or not you've read/skimmed it. I recommend at least skimming all of the sections that are pertinent to your type of aircraft and flight rules.

The second half of this book is the AIM (Aeronautical Information Manual). It's not the law, so you're not legally bound by this section of the book, but on the flip side, it's not the law, so it's actually easy to read. Tons of information is packed inside of the AIM, including things like airport markings, traffic patterns, communicating with ATC, navigation aids, etc. Some of the information herein can be found in more detail in other sources (advisory circulars, Pilot's Handbook of Aeronautical Knowledge), but this at least gives you a high-level view of important topics.

Every pilot should own a copy of this book. It is updated every year to reflect new regulatory changes. Buy a copy, highlight and bookmark the pertinent sections, and be aware of revisions by checking the FAR/AIM online at the FAA's website. ( )