Of course we have all heard the term "Dark Ages." I (and probably you, too) always had the idea that for about a thousand years, from the fall of Rome until the Renaissance, nothing happened. Life was hard and people were stupid. Hannam says we have it all wrong; plenty happened. As a matter of fact, our modern scientific process has its origins in the natural science studies of the Dark Ages, including even the careful, but unsuccessful, experiments carried out by alchemists.
Hannam documents various advances that Western Europe plainly made over the Arab world (stirrups!), and gives plenty of credit where it is due (the resurrection of the study of Greek). The entire book is fun to read, from the beautiful descriptions of the pursuit of physical science in the service of the "queen of sciences," theology, to the cringe-worthy medical science details.
Be sure to check out the medieval nose jobs. I am not making that up.
I'm not sure I would have picked up this book were I not teaching D's history this year as part of her homeschool. Hannam does a great job of taking something that I thought I knew, opening it up, and showing how things really were. I'll be looking for more books by him.