A condition book is the schedule of races for a given track for a certain period of time, typically a month or so. The condition book is written by the track's racing secretary (the person who decides which races the track will run). The condition book lists races for each day as well as a number of substitute races. These substitute races are used in the event that not enough horses enter a normal race to warrant it being used. The number one goal of the racing secretary is to write/schedule competitive races with full fields. The job of the trainers and owners is to find the place where his or her horse has the best chance to win. Due to this the horse owners and trainers are often at the will of the secretary, waiting for the right race. 

All condition books can be found at the Equibase website.