I have it, but I got so busy with other writing that I haven't written a full review yet.
I have quite a few Quint books but none of the racial ones so I can't compare this one to, say, Quintessential Elf or Quintessential Dwarf.
The book's author takes what I thought was a unique approach (and I'm really sorry I can't remember the author's name - I'm at work right now). Anyway, he created four (maybe five?) different Kobold "clans", each with slightly different racial modifiers and a unique outlook on the kobold's relationship to dragons. There's a lot of neat "fluff" story stuff in here about how the different clans came to be and their relation to each other, etc.
Coming out of that, then, the racial concepts each speak back to one of the clans. You can be any concept with any clan, really, but there are some more natural match-ups.
There's all the regular stuff in here - PrCs, Feats, etc. Tricks of the Trade included some unique ways that Kobolds use different types of skills and also included kobold combat tactics - basically, ways that smaller races work together to defeat larger enemies. I think that's the chapter it was in - that stuff might actually have been in a separate chapter.
Tools of the Trade included a lot of unique items made from dragons which I thought was fun. There's some other things in there, too, but I can't remember them all right now.
Let's see - I think it basically ends with kobold lairs or that kind of thing. Let me dig through my CDs here and see if I have my copy of the PDF here with me and I'll post more later - or feel free to ask specific questions and I'll try to answer them for you.