Like Jim said, Leslie Stroebel's book is very comprehensive and I imagine the latest edition has more updated prices etc. I have the 4th edition and I have no need to get the latest edition. The Simmons book is merely a primer for absolute beguinners, think of the difference between a real novel and the Cliff notes...you get the gist of the idea but nowhere as thorough and IMO a waste of money I made the mistake of getting it and if you want it send me your address and I will mail it to you.