I consider books to be reloading equipment too. In the latest Handloader issue, the column inside the back cover listed several books the author considered to be essential to his library.
I have most of those he listed and discussed. One that he mentioned was the Lyman Reloading Handbook, 45th Edition, which I do not have. Since I am a book nut, I went to the used book sites looking for this one. Found several ranging in price from about $20 and up. As usual I procrastinated and only went back and looked again yesterday. Now there are far fewer of this book available and many of the prices have shot up unbelievably high. One site only had 5 available and the $20 was still listed, where before there were 2 pages of available books. It looks like I'm not the only one that goes to the used book sites.
Another site had 5 listed priced from $58 to $258. Not sure if these dealers expected anyone to buy at those prices.
I still wanted one so I went to Cornell Publications and ordered one of their reprints for about $26 including shipping. My experience with Cornell is they provide high quality reprints.
Because of my OCD, I checked my library after seeing the author claimed there were only 7 editions of Handloader's Digest. I have 18 editions. The last 2 or 3 were not nearly as useful as the earlier ones but definitely more than 7. I suspect that the internet put it out of business.
Sorry about the long post. I don't really expect any responses, just wanted to vent a little.