Waldo and Magic, Inc(1940)

Robert A. Heinlein

North Power-Air was in trouble. Their aircraft had begun to crash at an alarming rate, and no one could figure out what was going wrong. Desperate for an answer, they turned to Waldo, the crippled genius who lived in a zero-g home in orbit around Earth.

But Waldo had little reason to want to help the rest of humanity — until he learned that the solution to their problems also held the key to his own...

Magic, Inc.
Under the guise of an agency for magicians, Magic, Inc. was systematically squeezing out the small independent magicians. Then one businessman stood firm. With the help of an Oxford-educated African shaman and a little old lady adept at black magic, he went straight to the demons of Hell to resolve the problem — once and for all!