Expensive, but you can immerse yourself for days in the mechanical wonders. I still remember learning about Geneva Mechanisms in the book. All that is gone now, of course, replaced with electronic control of motion.
Just as some of the other responders have discussed the intimate feel of holding a book, similarly is the feel of fine machinery. A while back I indulged myself in buying one of the finest pieces of excellent machining that I believe exists; the Curta Calculator. I have not regretted this rather unnecessary purchase as every so often I exercise my mind while 'feeling' the sensuous synchronization of fine gearing. An amazing piece of machinery with an equally amazing history.