Doc Savage made it to the radio three times: 1934–35, 1943 and 1985.
The 1934–35 episodes were 15 minutes each and were written by Lester Dent.
The 1943 episodes were 30 minutes long.
All the scripts were credited to Lester Dent; no recordings of any episode, nor records of cast or crew exist.
[1] The 1985 National Public Radio episodes were 30 minutes each.