If you're interested in thermionic valves in circuits the following may be useful:
- Terman, F. E., Electronic and Radio Engineering, McGraw Hill, Fourth Ed. 1955
- Langford-Smith, F., Radiotron Designers Handbook, RCA, Fourth Ed. 1953
- Jones, M., Valve Amplifiers, Newnes, Fourth Ed. 2012
- Jones, M., Building Valve Amplifiers, Newnes, Fourth Ed. 2012
- Williams, E., Thermionic Valve Circuits, Sir Issacc Pitman and Sons, Third Ed., 1953
It should be possible to get a wide selection of out of copyright books from tubebooks.org
both about circuit design using DC - UHF vacuum tubes and about tube construction and design. Material about microwave vacuum devices will probably be found elsewhere.