I think one should always be leery when confronted with the term "insider's guide". . .unless that insider is former jockey Donna Barton Brothers, and she's writing about horse racing in her book Inside Track. Even if you are not a huge racing fan, you have seen her at the Kentucky Derby, interviewing the jockeys and generally keeping audiences abreast of what's interesting and what's new at the Derby. She gets to do many of her interviews on horseback--there is a great picture of her doing just that on the back of the book--and just because of the image of her in the saddle, reins in one hand and microphone in the other, I believe that horse people respond to her the most of all the racing commentators.
Brothers was born into racing with a mother who was a history-making jockey in her own right, someone she refers to often in the book (and there are great Barton family photos here, too.) "You may have noticed I'm very proud of her," she writes; easy to see why. Her siblings have ridden race horses, and she's married to a trainer.
Between her lineage and her own experience as a jockey and racing correspondent, Brothers knows an inordinate amount about racing, and also knows a lot about distilling it for a general audience. This book is sort of like having that mounted guide along for any race. Brothers covers topics such as what to wear to the races--grandstand attire (comfortable shoes) to big day attire (often coat-and-tie.) She tackles big tough questions such as "Are races fixed?" (No.) And she covers the smaller, but equally thorny, questions about prep races and trifecta boxes, quarter poles and fractions. She details a day in the life of a trainer, and what the jockeys are saying to each other before each race.
Actually, the whole book itself is a bit like one of those jockeys: it's slender, it's compact, and you need it if you're going to the races.