My list from more then 30 "tube books" I own - here it goes:

1.) "Valve Amplifiers - 3rd edition" by Morgan Jones
(The best new, and one of the best all times "classics")

2.) "Modern High-End Valve Amplifiers" by Menno van der Veen
(Math & easy explanatory level, OPT theory, practice, OPT+tubes interactions - from easy to complex)

3.) "Radio Designer`s Handbook - 4th Edition" by F. Langford Smith
(Encyclopedia)

4.) "Das grose Roehren Handbuch" by Ludwig Ratheiser
(reprint from 1954. - German engineering precision at its best, more then 4000 tubes with diagrams, tabellas, theory and practice, etc.)

5.) "Roehren Taschen Tabelle" by Jurgen Schwandt
(little tube manual with 3000 tubes, every tube "described" with tabelle with 35 parameters, etc. Reprint from 1975.)