In his third book about Doctor Dolittle, Hugh Lofting returns his hero to west Africa, where he helps a peaceful African tribe. 

There are multiple stories in "Doctor Dolittle's Post Office". The primary one is featured in the title and tells of how John Dolittle establishes a post office in a small African village - first, to help the residents send messages to one another; but soon expands to send messages to and from other countries using migratory birds to carry them. He even allows animals to send messages across disparate continents. 

In addition to the titular story, we hear of the Doctor helping to capture a slave ship, fending off attacks on the peaceful village from other tribes, and his visit to an ancient turtle living in an isolated region of Africa, who remembers the time of Noah's Biblical flood.

As an intermission, we even get a few short stories told by Dolittle's animal friends.

Doctor Dolittle is a physician turned veterinarian, who learned the language of many of Earth's animals and spent his life helping people and beasts. This is another entertaining book by Lofting that focuses on the Doctor's kindness and the respect that it brings him.