No, its fine for cluelesss people but I think its a joke.
One of the biggest disasters people make is trying to use the previous years results at a meet. Its hysterical. I mean its ludicrous to think that because a trainer had a bad meet the year before or three years ago that he is going to definitely have one again. Trainers are dependent on their stock and stock varies from year to year. Obviously guys like Pletcher who maintain a strong string year in and year out are going to win races but do you need a book to tell you that?
Also the trainer jockey combos are a joke. Jocks switch agents a lot these days and its usually the agents that trainers work with when they want to put one over at a nice price, it just happens to be their jock that they ride.
All these books do is state the obvious. For example I bet they profile Chantal Sutherland as a "dangerous" spa grass jock because she won a few at long odds last year. Lets face it, she caught a few live mounts and won a few. That does not change the fact that she is a mediocre jockey at best and not someone you will look to bet just because she is on a horse.
Save the money for something else. You can always ask Steve, Joel, Blackthroat, or I about something on this site for free anyway so why the hell would you lay out the cash on some book thats going to state the VERY obvious and often state it in a horrible context?