Charts Made Simple by J. C. Briar seems small in your hands, but packs a punch.
The book is broken into 6 chapters, ranging in topic from The Big Picture and Staying on Track to Charts That Show Shape.
One of the most interesting things about this book, for me, is that it reads and feels like a correspondence course. There are exercises in the back of each chapter, and answers for most of the exercises are given at the back of the book.
Another fantastic thing about this book is its great use of drawings, charts and photographs. They are all used to the best advantage possible, to guide the knitter into the world of charts.
Also, JC points out that any knitter, even if they knit in unusual ways, can use charts easily and well.
JC also has some cute tips on making the chart-reading experience easier for everyone. Is your chart too large to use on a regular magnetic board? Use a cookie sheet. Brilliant!
Even veterans to the world of charts should take a look at this book. The chapter on cables is simply amazing.
I heartily recommend this affordable, useful, thoughtful book to knitters of all experience levels.