I bought it for my son - he was building a rock crawler.
Someone mentioned a Carroll Smith book. I have Prepare To Win - good book. I have read that all of the Carroll Smith books are supposed to be very good. He has a suspension design book that may be less 'engineerish' than the Milliken book.
For suspension - Carroll's Tune to Win is a good basic book. If you want to get into more advanced stuff, Gillespie's Fundamental of Vehicle Dynamics has pretty much everything you'll need in it. RCVD is an outstanding book, but a very hard read for someone starting out.