I didn’t see the Rwanda Bradt Travel Guide until I had already bought another…..and I shan’t make that mistake again! I went to Rwanda a couple of times in 2007 and greatly enjoyed my time there. Read all about why in this up to date version, which is likely to pay for itself several times over as you seek all the best places to visit.
Another one to consider if you are going to be travelling around quite a bit in the region is the favorite books from the Lonely Planet stable. This one (soon to be updated though) covers the whole East African region.