I've been looking for a book that is the complete handbook of crochet - like the Montse Stanley handknitting book, but for crocheters. The MS book has about 20 different methods for casting on, the same for casting off etc - when most folks probably only know one or two methods.
So far I haven't found anything, so instead I'm collecting links to useful stuff online. I'm all about the crochet at the moment, it's so much easier!
These are all interesting techniques that aren't in most beginner's crochet books.
Future girl - foundation crochet
Foundation crochet from Carina's craftblog
Foundation single crochet
Foundation single crochet - double base chain method
Symbol charts here and here
Invisible fastening off
Keeping the seam straight when crocheting in the round
Crochet sphere calculator
Linked turning chain
Crochet Liberation Front - useful videos
Videos from TXCr1cket - chainless starting stitches, conjoined dc, chainless foundation
Crochet Kim's youtube channel - tunisian and crochet
Base chain redo
Slip stitch crochet