Knowing little about Islam except the difficulty of finding a balanced viewpoint, I bought this book and `The Truth about Mohammed' by Robert Spencer in the hope of finding out.
Whereas Spencer's book is an outright condemnation, Armstrong is mild in tone. Yet the accounts she gives confirm some of Spencer's accusations, while leaving the reader to draw his own conclusions. For instance, she tells the story of Mohammed's revelation justifying the attack on the Qureysh caravan at Naklah apparently without emphasizing the difficult precedent which this set (p. 130). Also the reaction of Mohammed's favourite wife Aisha to the revelation justifying the marriage to Zaynab (p. 168) "How convenient! Truly thy Lord makes haste to do thy bidding!"
Most of the book is a rather rambling and confusing biography which does however give a convincing picture of a lawless society ruled by violence. A religion born in such circumstances needs a lot of interpretation to be acceptable to the modern world.
A prophet for our time? Armstrong's contention, in contrast to Spencer, is that Mohammed was a man of peace who was forced into warfare and banditry by the violent times in which he lived. I think Armstrong expects the reader to read between the lines.