We have used this book to help us learn about mountain biking in Spokane. It has some good information for beginning to find your way to good rides, but a number of the rides are out of date. For example, the Minehaha loop ride has some trail changes and improvements not mentioned in the book. More importantly, at least one ride, Marshall Dips, is no longer rideable due to ownership changes - the trailhead and areas on the trail have "No Trespassing" signs. Another ride, Garden Springs, has some sections that are changed or missing due to new development.
So, this book has some good info, but don't count on it to get you through the whole ride. Be prepared to do some route-finding or change your plans.