This is a handy and practical work for the GM, detailing several (oh, all right, ten) street gangs, of the size that will pose a realistic yet not overwhelming threat to the characters - or become potential allies. Because it is written 'in character' extracts can be used when the 'runners do some research on gangs they've encountered as well.
So, what is a 'street gang' anyway? You probably have a mental image of leather-clad biker toughs, or something like the Jets out of West Side Story... could be, but there are a wide diversity of possible groups to be found, with a range of different capabilities and interests. For all of them, though, 'reputation' is an overwhelming priority, that and the good of the gang as a whole. Mechanically, each gang described is looked at in terms of the reputation of the gang, what sort of threat they pose to those who encounter them, an estimate of the number of members, and information about their professionalism and skills. Professionalism? you might ask. Like anyone else you have dealings with, it's nice to know whether they'll actually keep a bargain and are reliable...
Like the real world, many gangs draw their membership from inhabitants of a neighbourhood or members of a specific ethnic group. Some can be transported to wherever you are running your game, others are embedded in a specific locale and will add local colour if your 'runners need to visit that location. Many of the individual listings mention other gangs in passing: rivals or allies in the main, if you wish to delve deeper into gang culture you can develop these further, using what's here as a guideline.
Each entry also includes notes on the history and prominent members of the gang, as well as their territory and main areas of business. There are also plot-hooks suggesting how you can involve them in the characters' affairs, some might make full-blown adventures. Despite its size, the work is jam-packed with information and ideas, I can feel plots spawning even as I read through it. If you want to bring gang culture and mentality into your game, this is well worth getting.