I have Volume 2 and its a very good
reference despite the omission of sliding collision (though its noted in the chapter contents!).
Volume 2 concentrates on 3d, texturing and lighting.
They are expensive but worth it in the long run if you're serious about DBP.
I've also got the Beginners Guide to Darkbasic Programming - its a bit dated now but still has some very useful content and general background / good practice procedures for games programming, along with some good example code (and a CD). Not sure what the overlap is between Hand On Vol 1 and the beginners guide, or if this one is still available but it could be an alternative to getting Vol 1.