Here are my most useful favorite books about toolmaking.
Making and Modifying Woodworking Tools
I really like this book because of the process he walks the reader through in making a tool. It also includes necessary metalworking techniques, and other specialized toolmaking related skills. I highly recommend it, though it is out of print now, and hard to find. I got mine used from Barnes and Nobles.
Making Traditional Wooden Planes
-John M. Whalen
The title pretty much sums it up. It is more narrow than Kingshott's, and slightly slower read, but has some excellent information. Whalen also has another book on wooden planes, but I haven't read it.
The Fine Art of Tools
The first two books are really how-to books. This book is a book of inspiration all in pictures. Nagyszalanczy also has another similar book, but again, I haven't read it.
Now there are definitely other books on this subject, but these are just the ones I've read. Feel free to comment to add a book you've read, and liked.