A new Hornady reloading manual was just announced and will be available on December 1. I’m expecting that the 11th Edition Hornady Handbook of Cartridge Reloading will be an worthy successor in a line of excellent handloading books from the company.
I bought my first manual (actually, it was a two volume set) back in the mid- to late-90’s and I used it to both develop loads and just learn about cartridges. When I purchased the set, I was only loading for the .38 Special. Since then, I’ve added a few more calibers, but the Hornady manuals are still a staple on my bookshelf.