I just finished reading both of these books-

Safari Rifles by Craig Boddington
Rifles for Africa by Gregor Woods

Both are excellent and full of great info. Boddington takes the approach of giving a great deal of information on all types of rifles, calibers and bullet types with recommendations for specific animals. All in all, a very solid body of work with a great appendix showing his research/questions of a large number of PH's and what they recommend for Africa.

Woods' book has a great intro with a bit of history about the development of African weapons. He starts with the first European/Arab hunters and comes to the present. He presents much stronger opinions than Boddington on bullet type, caliber and his philosophy on what calibers to use on which animals. He favors heavier, bigger diameter bullets on most Africa game. He has a wealth of direct experience with a vast number of calibers and bullet types to talk about.

Both are excellent and match what our famed Bill Stewart says in his book on Elephant hunting.

Both are good books and you cannot go wrong with either. If I had to pick just one - I would go with Woods' book due to the history and his opinions on bullets. If you cannot decide, just buy and read both.