This is a *massive* book (compared to most race books) covering four races--the kitsune, nagaji, samsaran, and wayang--in considerable depth. It contains about 150 pages worth of good stuff for these four races.
What kind of stuff? Well, it has two major sections, the race description section and the character options section. The race description section goes through each race in great detail, broken down into a number of subheadings:
*Facts and Falsehoods, each one having five commonly known facts and five commonly believed myths about each race.
*Life as a X, describing such things as physiology and life cycles for each race (including cool art sequences of a character of the race over their lifetime).
*X culture, covering the culture and relations of each race. As a 3rd-party supplement they can't talk specifically about Golarion lore, but most of the culture and such transfers without any problem.
*X ethnicities, detailing a variety of different ethnicities for each race, also with some great art illustrating them
*X origins, relating a few different origin myths for the race, great for mining ideas about the kinds of stories a race tells about itself.
*X religion, describing a god or philosophy that could be common among the race. Again, these aren't Golarion deities, so there's some translation required if you're playing on Golarion, but it's still good for idea mining.
*A section unique to each race, such as kyubi (multi-tailed kitsune) or reincarnation for the samsaran
After this section is the character options section, which is packed full of alternate racial traits, feats, archetypes, favored class options, and more. There's far too much to review, but the sheer quantity means that just about anyone playing one of the four races detailed can probably find something they'd like to use. Some of the options are even open to other races, being more Asian-mythology themed rather than something specific to a race.
Last is an appendix which includes starting ages and aging charts, height and weight charts, and random background generation charts.
All in all, there's a lot of great stuff in this book!