This is the one book that should be aboard every cruising sailboat. When the first edition came out, I read it cover-to-cover. When the second edition came out, a flip through the pages showed some updates, but basically it was very much the same book. When I had a need, I could find what I was looking for in either one (or in some cases neither one).
This third edition parts company with the first two editions. The basic organization is still there, but the material is very different, reflecting the latest developments in equipment and changes in regulations. There seems to be a lot more material in the third edition, probably because sailboats and the equipment have gotten a lot more complicated.
If you have the first or second edition do you need to pay the big bucks for the third edition? In most cases, yes. If you have an older boat that you have kept very simple and do not plan to make any upgrades, you might get by. Otherwise you will be glad to have the third edition on your boat’s bookshelf. I’ll probably have to have two: one for the office and one for the boat.