Mind Changer

It's where human and alien medicine meet: a massive hospital space station on the Galactic Rim, with 384 levels and a multispecies staff of thousands.
In the course of practicing deep-space medicine, that staff has seen more than its share of challenges--from plagues caused by cafeteria food, to cafeteria food that resembles alien species. But now they are facing a disquieting new development: the terrifying Chief Psychologist, Dr. O'Mara, has been promoted to head of the hospital.
Worse, he's been given the job on a temporary basis, for just as long as it takes to train his own replacement. After that, he is up for mandatory retirement. Nobody at Sector General can begin to imagine what they'll do without him--assuming they last long enough to find out.