Books? I don't need no stinking books! I just fumble around until something fits!
I have two. When I start something new, I like as much input as possible, I love math and love learning- stuff!!
The first book I bought was from the early 1900's and had diagrams dating to the 1800's. It explained the basics of operations and bit grinding and such but no tables. Fascinating they had figured out so much in a short time.
My second book of course is the 3" thick 21st addition machinists handbook (1980 print)- it has everything, every table, every answer to almost any question I would have. The original owner; Russell Kruckenberg, sure enjoyed it (Signed on first page).
I remember the first time I really opened the book and became immersed in it. The power went off for an hour or so in the winter, so by the glow of the antique oil lamps I had lit, I opened the book and began reading. I kept reading long after the power came back on. It was a good way to pass the time.
It's said we use only 10% of our brains, well, I used up that 10% and to input any more information, I had to lose some previously input information. So I keep the book near me when working in the shop.
The internet is nice, but stopping what I'm doing to go into the office and look up information isn't an option. Besides, there's nothing like reading a book, consulting a book. It's at hand, is easy and quick to open, it's already printed out, won't fail when the power is out, won't crash, and all you need is light and time.