There are five chess books that are out of copyright and may be downloaded for free as pdf files:
https://www.chessuniversity.com/arti...e-chess-books/
- Seventy-Five Chess Problems by John Thursby
- 121 Chess Problems by J. W. Abbott
- 200 Chess Problems by Frank Healey
- 777 Chess Miniatures in Three by E. Wallis
- American Chess Nuts by E.B. Cook, W. R. Henry, and C. A. Gilberg
