@shaulawalko @HamonWry My favourite was checking out a library book in the mid 80’s that had last been checked out in 1969. It had been sitting on that shelf waiting for me since before I was born. It was on the history of explosives, and if you read the whole thing, contained enough clues for you to be able to make various old school explosives. It led to a rather serious conversation with my high school chemistry teacher after I asked about titrating acids.