I bought it and found it
fairly useful.
I disagree with doomwad though,
Quote: "mainly assumes you have darkBasic proffesional"
I would say for the most part it is for DBC users. Certainly the help file on the CD is for DBC commands only, there are no DBP ones in there.
The one chapter that I found extremely helpful was the multiplayer chapter. It talks you through creating an online multiplayer game.
If you are a complete beginner then I would say this book is great, if however, you are slightly more advanced then you will only find one or two chapters helpful.
Overall, IMHO, not worth the asking price. If you can find it on a sale somewhere for 50% off then it would be worth it.