The Hesperian Foundation in Berkely, California, developed the above-titled book 30 years ago which has meanwhile been translated into 80 languages, including Tok Pisin (the PNG Pidgin).

It is written for volunteers, community leaders, health workers etc. with medical and non-medical backgrounds, in simple language. In fact, the writing style and especially some illustrations are blunt to the point of being hilarious.
We used this book (in Spanish) when living in rural Honduras and were amazed at its amazing cultural insight and pragmatic approach specifically to medicine in the 3rd world. The publisher allows copying of any parts of the book (if not for commercial use) which we did in Honduras in the form of posters in the waiting area and handouts in order to empower patients to take control of their health. While literate patients could easily understand the text, illiterate patients could study the in-your-face 'diarrhea comics', for example.
“Where there is no doctor” can be downloaded (together with other books) and a new, 21st edition is in the works:
http://www.hesperian.org/publications_download_wtnd.php
One of the most useful and ingenious tools the book offered us are the 'non-reader labels', an easy and fast way to convey to patients how to take their medicine (see last 2 pages of link below):
http://www.hesperian.info/assets/WTND/WTND_Chapter_8.pdf
But this is just the tip of the iceberg. The Hesperian Foundation website offers a vast list of medical literature and resources for medical, dental, even veterinarian services in the 3rd world. The links are worth checking out if one has the time and interest.
If nothing else, this and undoubtedly other publications on the publisher's website offer valuable insight into the mindset and reality of medicine in the third world.
Main website: http://www.hesperian.org/index.php