'Dinosaurs' was, IIRC, the first How & Why I owned; 'Ecology' the last I bought or was given (by that time, the American focus of their biology books was beginning to irritate me, making me think there should be an Australian equivalent). I also remember owning 'The Moon' (10th birthday present, a few weeks before Apollo 11), 'Stars', 'Planets and Interplanetary Travel', 'Prehistoric Mammals', 'Early Man', 'Reptiles and Amphibians', 'Birds', 'Rocks and Minerals', 'Beginning Science', and I know my sister owned the 'Ballet' book. 'Time', 'Weather', 'Coins and Currency', 'Insects', 'Oceanography' and a few others we either owned, or borrowed from libraries.

Where are they now? Well, my mother was a teacher at a small private school, so they tended to end up in her school library. But I think they deserve some of the credit and/or blame for making me the geek I am today.