I have been knitting for a long time now and am quite addicted to knitting books. I always ask for one when asked what I’d like for a gift.
For me they fall into several categories:
technique, template, stitch library, design, designer, inspiration, knitlit
I have favourites in each.
Technique: Vogue Knitting and the Big Book Of Knitting, Sally Melville’ Knitting Experience series (Book 1, Book 2)
Template: Ann Budd’s Handy Book of patterns, AB’s Handy Book of Sweater Patterns and A Knitter’s Template
Stitch Library: Barbara Walker’ Treasuries (Book 1, Book 2, Book 3, Book 4)
Design: Deborah Newton’s Designing Knitwear and Maggie Righetti’s Sweater Design in Plain English
Designer: Meg Swanson, Sally Melville, Kaffe Fassett, anything Rowan puts out
Inspiration: Kaffe Fassett books, art books
Knitlit: The Knitting Sutra, Knitlit
This is just the tip of the iceberg of the books available so I am sure you’ll get as many different recommendations as there are posters to this board.
I would recommend borrowing as many as you can from the library or friends or browsing in Barnes and Noble to see which ones suit your current needs and fancies.