I'm currently reading "Hadrian and the Triumph of Rome" by Anthony Everitt.
This is a good book for people with a more than passing interest. It covers the roughly 60 years years between the Flavian Emperors and Hadrian's death.
The author does a good job explaining the political and historical conditions that preceded Hadrian's rule. Everitt offers interesting and reasonable speculation where the historical record is thin, especially during Hadrian's youth.
Hadrian spent most of his adult life away from Rome. He traveled the width and breadth of the empire, commissioning architectural projects, founding towns, and making sure the legions didn't get too restless. His historical record isn't as rich in documents and secondary sources as for other emperors, so Everitt had to travel far to piece together details from the architectural records, taking pains to find relevant inscriptions and dedications etched in stone and metal.
Hadrian was an interesting and enigmatic emperor. He was a good administrator, a Hellenist, a solid military man with a curious and artistic personality. His one "big idea" was to stop expanding the empire, build walls around those who could be governed, and stomp on those who couldn't.
I'm halfway through the book and will provide a more detailed review when finished. So far, I'm finding it rich in detail and context and well written for casual history buffs. Classics scholars may enjoy the sweeping overview but will probably be left feeling hungry for more.
RSG