This book is widely used in the entertainment industry for giving directions to studios, location shoots, etc. Agents and Casting Directors are often extremely busy and don't have time to give out detailed step-by-step directions over the phone, so by using the Thomas Brothers Guide, they can just give out a quick map coordinate thus saving quite a bit of time and avoiding confusion.
One important note about commuting in the greater LA area... LEAVE EARLY! The horrific traffic situation in LA is a well known fact of life. But it is never an excuse for showing up late on any interview, audition, or call time. You are expected to leave early enough and give plenty of time to compensate for traffic jams. If you want to burn bridges fast in the entertainment industry, just start showing up late for appointments. You will be back on the bus to Timbuktu in no time.
Speaking of buses.... having a motor vehicle to get around Los Angeles is a huge advantage, but one can use the public transportation system, as I did when I first moved to LA. The public transit system in LA is called Los Angeles County Metropolitan Transportation Authority. Their website has everything you need to get from point A to point B on time, including an easy to use trip planner. Here is their website:
Los Angeles County Metropolitan Transportation Authority