Vacuum Tubes in Wireless Communication

More early reading on vacuum tubes. To be honest, I never really understood (or frankly studied) the physics of semiconductors, which always seemed a bit abstract to me. Having read some of these early texts on how vacuum tubes work, they seem fairly straightforward by comparison. I wonder if I go back and read some introductory semiconductor texts, whether they will seem more straightforward now?

Anyway, another nifty classic text on Google Books: