If you like making things by hand, the old Machinist's Handbooks are also really good to have, with lots of old but still fascinating, and even occasionally useful stuff in 'em.
I love these, old books on engineering design, and historical technical drawings. The cost of errors must have been astronomical before CAD and Ctrl-Z. I can only imagine how much focus was required to do the complex shadings and exploded diagrams we now take for granted.