I've got eight or so of them, including The Universe and Mathematics. For a while there near any roaming used-book-store on the campus where I used to be employed would include a bundle of these books, and I'd have to decide how many of them I really wanted to add to my pile. I haven't read any from cover to cover, but they do make fascinating skimming, particularly in things like The Planets or Men In Space where things are so hopelessly out of date that they become intriguing all over again.