Chris Malta's book does have some valuable tips - he has a lot of experience dealing with wholesalers - so it's definitely worth a read. However, in my opinion, you can find information that is just as helpful from reading the eBay forums and other lively ones such as this one :
Books are great reference points, but I advise checking the publication date when reading a book about anything on the Internet including eBay: anything older than a year or two will be out of date.