This omnibus edition contains 3 of the first 4 Sector General novels. Sector General is a huge hospital in space, with sections that reproduce the environments of all know sentient species.
Dr. Conway begins his work in this bewildering environment in the first book, Hospital Station. He gradually adapts and advances through the series. The second book is Star Surgeon and the fourth is Major Operation.
The 3rd book, The Aliens among Us, is a group of short stories with only one that deals with Sector General.
Unfortunately, the first books suffer from typical 50's & 60's SF attitude toward women. That is that they are decorative but not too bright. And they are never presented as fully conceived characters. You can see this especially well in Nurse Murchison, Conway's love interest and later, wife.
However, unlike most writers who displayed this attitude, White was able to improve his female characters as the series progressed.
Anyway, the problems are fairly minor. Over all this is a consistently entertaining series with many imaginatively conceived aliens. You'll like it.