Have you read the Belisarius book by Lord Mahon??
There aren't many books around about this great Roman, Mahon's book was written in the 1800's so is obviously quite old fashioned in its reading but still very good, although it does rely heavily on Procopius where as Ian's book gives us a much wider insight into the life of Belisarius.
Both are excellent books, although Ian's in probably the better and more entertaining of the two, Lord Mahon's is still worth reading.