The books below are all, I think, approachable and readable, as well as educational, even if they're not always the most scholarly of works - and despite that, or because of it, their authors should be commended. They're light on footnotes (if they have them at all) and jargon, full of engaging stories and colorful characters. Some are a little more serious, others are like really, really good historical novels (The Speckled Monster, for instance, is basically a novel based on good research that's followed by a short bibliographic essay).
A World Lit Only By Fire: the Medieval Mind and the Renaissance - Portrait of an Age
William Manchester
New England's Generation: the Great Migration and the Formation of Society and Culture in the Seventeenth Century
Virginia DeJohn Anderson
The Island at the Center of the World: the Epic Story of Dutch Manhattan and the Forgotten Colony That Shaped America
Russell Shorto
The Speckled Monster: a Historical Tale of Battling Smallpox
Jennifer Lee Carrell
Crucible of War: the Seven Years' War and the Fate of Empire in British North America, 1754-1766
Fred Anderson
A Midwife's Tale: The Life of Martha Ballard, Based on Her Diary, 1785-1812
Laurel Thatcher Ulrich
This Republic of Suffering: Death and the American Civil War
Drew Gilpin Faust
The Warrior Queens: the Legends and Lives of the Women Who Have Led Their Nations in War
Antonia Fraser
(quite light, but interesting and fun, and a good jumping-off point for more reading)
