Tooting my own horn... my buttons on the pages of a book!
I bought Ysolda Teague's book Little Red in the City a while ago, and read it from cover to cover (and squealed when I saw my buttons).
It has patterns, and they're lovely, but the real beauty of it is the way it's written. Every pattern has a proper schematic showing how the pieces of the garment fit together; stitch patterns are charted as well as written line-by-line; yarns are described in terms of the fabric they create as well as their weight and fibre content. Complete measurements are given for each size, including measurements you didn't know you'd need (until you do), like cuff measurements. Just looking over a pattern is an education in pattern-reading. The side-by-side chart and row instructions make it clear how charts work, and will probably have you able to 'read' your own knitting in no time.
Most of the book is about fit, measurements, and modifying pattern instructions to fit you. I must admit that I read this part rather grudgingly. Too much information, I thought. I don't want to become a knitting designer, I just want to make clothes. I'm lucky enough to be able to find things that fit in standard sizes in shops, so I don't need to deconstruct patterns to this degree.
But it all sank in, and this weekend when I was sewing t-shirts* I found myself blithely re-drafting patterns, tracing patterns off other clothes, and knowing what was wrong with the fit on the first go, sometimes even before cutting a piece of fabric.
Even if you don't ever plan to knit one of Ysolda's designs, this book will help you choose and use other patterns intelligently. And it may even improve your sewing.
*photos to come when the light in Cape Town improves enough for indoor pictures of dark blue garments.