The Greatest Knight: The Remarkable Life of William Marshal, the Power behind Five English Thrones by Thomas Asbridge (nonfiction 2014)

Humanity was lucky enough that someone found the only copy of Guillaime de Mareschal's biography, and this book uses that and other sources to reconstruct Marshal's long and amazing life.  It's a great read especially for non-fiction, even if you know nothing about the Angevin Empire.

The Battle that Stopped Rome - Emperor Augustus, Arminius, and the Slaughter of the Legions in the Teutoberg Forest by Peter S. Wells (nonfiction 2003)

I've read and enjoyed Wells' The Barbarians Speak, and this one is very exciting too.  While there isn't much new or different in the part about Augustus, the sections on Varus and Arminius are wonderful.  The reconstruction of what happened at the battle based on the extensive evidence is absolutely gripping, horrifying, amazing.

The Zealot by Simon Scarrow (historical fiction 2006)

Overall Scarrow writes a pretty good yarn, and it's fun to tramp through a different landscape with Macro and Cato this time.

The Roman Guide to Slave Management: A Treatise by Nobleman Marcus Sidonius Falx by Jerry Toner (nonfiction 2014)

Sometimes when authors try to summarize thousands of years' and millions of people's experiences, it gets muddy, but this is really good.  The format of the book sees Toner take on a persona of a Roman nobleman, then give analysis in his own voice at the end of each chapter.  It works because the explanations do explain without being long-winded, and Toner gives references to multiple primary sources.

Attila: The Barbarian King who Challenged Rome by John Man (nonfiction 2006)

Engrossing study of the times and the land that knew Attila.  Long aside about shooting arrows astride horses and the technical aspects of the Hunnic bow, nice for military information.

Legionary: The Roman Soldier's Unofficial Manual by Philip Matyszak (nonfiction 2009)

Full of illustrations, takes pains to identify changes over time in many aspects of the army.  Ruined by too many stupid jokes.