Perhaps my favorite thing is how Kobolds of Golarion reworks the kobold race, making them far more intelligent and cunning than depicted in traditional Dungeons & Dragons or works like Kobolds Ate My Baby (ALL HAIL KING TORG!), but still with the knowledge that these are far from the most dangerous creatures out there. The argument for their reputation is that the less valuable members of kobold society are sent on patrol duty and are usually the ones adventurers encounter. All of this is part of the complex exploration of kobold psychology, physiology, and culture. The kobold race's connection to dragons is emphasized and played around with, discussing the ways in which kobolds work with, serve, and sometimes worship the great wyrms.
Kobolds contains a great resource for GMs in its look at various tribes around Golarion. Containing seven tribes each from a different environment, each entry includes information on the tribe's activities, physiology of its members, leadership, allies, and enemies. Everything from a more traditional tribe serving a great dragon to a clan that have taken to shipwrecking for survival and calls their chieftain captain is present here. The book even provides a map of the snarl (the underground set of tunnels where kobolds live) of the Embermaw Clan, which looks like an ant's nest in its complexity and is painstakingly detailed and notated by a couple of the clan's members. This snarl map alone is a great resource for GMs wishing to create a kobold centric dungeon.
Players looking to play a PC kobold are also well served. A whole list of new racial traits are available, including the ability to take on a prehensile tail or the ability to see in sunlight without disadvantage. Several new kobold-themed archetypes are introduced including the Dragon Herald for Bards, the Snare Setter for Rogues, and the Swarm Fighter for Fighters which emphasis the races connection to dragons, ability with traps, and talent for fighting in great numbers, respectively. Personally, I really dig that Dragon Herald and the close-relationship that could be played off with a dragon NPC. Like all Player Companions, Kobolds of Golarion includes a decent list of new feats, spells, and equipment with a mix for both kobold specific and non-kobold use.
There are two sections that stand out, and the first does so in a truly vibrant fashion. Kobolds come in a wide variety of scale colors: all of the chromatic dragon colors and a few other rarer ones. The coloration section tackles optional traits for kobolds of a certain scale color like a reflection of a red dragon's breath in a red kobold. My favorite subsection is the rarer colors, some of which are outrageous and some of which serve on their own as perfect roleplaying fodder for a kobold PC.
Get your search check ready, because the second highlight section is all about traps. Whether a GM or a trap-based Ranger or Rogue, the traps in Kobolds of Golarion are delightfully wicked, with many of them serving an alternate purpose, adding more tricks to the trapper's arsenal such as a Distraction Trap designed to slow an intruder by overwhelming their senses almost like a flashbang grenade. A subsection also goes into further detail on extra defenses kobolds will have prepared for their snarl. Slaying kobolds may be relatively easy but getting to them unmolested, now that's considerably harder! Better hire that expert Rogue.
Pathfinder made goblins cool (and cute!) again, and now the little, football head-shaped monsters have some real competition, because with this book kobolds have been given more bite than ever before. Kobolds of Golarion is exactly what players looking to play this monster race need and is a useful GM supplement for those who wish to emphasis traps, dragons, and of course, kobolds. King Torg would be proud.
PS: ALL HAIL KING TORG!