If you cart your books around long enough they turn into a library but also a snapshot of your brain. I have carted some of my childhood books around long enough to see those snapshots. When I was in 11 and 12 years old I went through a World War II phase and especially a tank phase. For that couple of years, I asked for books on tanks for my birthday and Christmas. I've carted them around and pulled them out. Here’s my collection from years back plus one recent book.
Part of a series, Macmillian Pocket Encyclopedias in Color. By this time, I was getting more obscure with my "tank phase" and wonder how I picked it out. WWI takes were not as interesting as WWII tanks--they were usually big bulky mountains of metal or lightly armored cars. One of the Russian Armored cars, the Garford is shown with a Skull and Crossbones.