Where do we start? So many books, and the more you look, the more you find. I've split them into categories, and added a bit of a comment where it might help:
General
- Sahara Overland - Chris Scott
- Vehicle Dependent Expedition Guide - Tom Sheppard (like hens teeth and rocking horse poo, if you see this - BUY IT!)
- Travel Vans - John Speed (loads of details on converting a van into a decent motorhome, in laymans terms)
- Weather to Travel - Maria Harding (useful overview of good/bad times to visit every country in the world, comments on temperatures, rainfall, general weather patterns etc)
- Africa By Road - ??? (a great starting place for anyone thinking about overland travel, no jargon and easy to understand. Also has a number of suggested routes and country descriptions, although these are slightly out of date, as is the way in Africa!)
Medical
- Expedition Medicine - David Warrell & Sarah Anderson (recommended by the RGS - hard to find but a reprint is coming out September this year...)
- Where There is No Doctor - David Werner and others (village healthcare, laymans diagnosis of illnesses, with hand drawn pictures so you can better overcome a language barrier if needs be)
Cooking
- 70 Traditional African Recipes - Rosamund Grant (with a good overview of all the weird and wonderful food we're likely to come across in the markets!)
Non-Fiction
- Lois on the Loose - Lois Pryce (very well written book all about a Lois and her motorbike adventures from Alaska to Argentina. Good to read around other peoples travels, even if they're not with the same vehicle or in the same country!)
- Long Ride for a Pie - Tim Mulliner (solo push bike trip from the UK to New Zealand)
- Tuk Tuk to the Road - Jo Huxster (a pink tuktuk trip from Bangkok to Brighton)