The (much slimmer) volume that may help you is edited and translated by Harry Turtledove (University of Philadelphia Press, 1982).
The 'fellow named Mango' is Cyril Mango, the great Byzantinist, and the volume you are referring to is huge. If you could get it from your library, it would be worth the effort. In the meantime, the Turtledove translation is good.
You might also look at C. Mango, Byzantium: The Empire of the New Rome. But it will depend on exactly what you are trying to do, and to the scope of your work.