My mum showed me how to knit when I was a child but I wasn't very good at it. As an adult I picked it up again from time to time but never really "got into" knitting until I found Stitch 'N Bitch by Debbie Stoller.
Knitting's not just for old ladies! Who knew?
The book is written in a "young" and irreverent style. It is stuffed full of knitting patterns for things you actually want to make. But where it really wins in my opinion is the clear instructions for every knitting activity you could wish. Knit and purl stitches, casting on and off (lots of different ways) sewing up, plus the odds and ends like increasing, decreasing, making a buttonhole or a picot edging and so on. This book contains everything you need to know.