Full of Opportunities
"NPC Codex" by Jason Bulmahn & friends, published and distributed by Paizo Publishing.
The very short introduction tells you how to use this book, and gives info on how the stats blocks will be laid out.
Part One, "Core Classes", breaks down each of the 11 Core Rulebook character classes into 20 examples, one for each level. Some of them might make for good friends of the player characters, and some of them are better off as villains plotting against the players. In any case, there are still plenty that are just plain NPC's that can be used in your game. There's also the nice feature of being able to find out what each character class is capable of at =every= level. From Barbarians to Wizards, there are portraits of each, and at least the same basic info you'd find in a Bestiary.
Part Two, "Prestige Classes", covers the 10 Core Rulebook Prestige Classes, with four good examples of each, from Arcane Archers to Shadowdancers. Each has a character name and a short description of who they are, what to expect if in combat, and role-playing suggestions. The major differences between each character point out that there is a wide diversity of choices for each class.
Part Three, "NPC Classes", only has the five Core Rulebook examples, but the 10 of each gives GM's many prospective city or country inhabitants. They would also make for fine allies, friends, or enemies. There are 10 example levels for each class. From the first level Adept to the 10th level Warrior, these characters can help to really flesh out a world.
Part Four, "Iconic Characters", studies the same 11 core classes as part one, but instead of making each one different, this book assigns a single character per class. For instance, we follow Amiri the Barbarian as she advances from 1st level to 12th level, with stats for 1st level, 7th level, and 12th level. This was my personal favorite section, as it shows offensive abilities, defensive abilities, tactics, and a stat block. This shows how a single character can develop.
There are three appendices: Animal Companions, Encounter Groups, and a class feature index. The Animal Companion section details possible Druid and/or Ranger animal friends, and even how they might level up themselves. The Encounter Groups section breaks down various bands of NPC's at low level, mid-level, and high level. Great for that random encounter. The Class Features section is merely an index to where the various features can be found. There's also an index.
I'll start off by saying that originally I was not planning on purchasing a hardcover version of this book. I usually take my laptop to gaming sessions that I run, and the fine Paizo PDF of this book was all I thought I needed. But the PDF convinced me that the hardcover version was useful - especially when planning the next adventure at home. I would like to urge Pathfinder GM's still sitting on the fence trying to decide if they want one to take a look at one and see what a great job Paizo is still doing, especially with their hardcovers.
Highly Recommended - especially for GM's.