There are so many great books to recommend that any list will be only suggestive, not exhaustive. These are books I have read recently, or am reading.

Currently I am reading two books from the Founding Era, and finding them fascinating accounts of the establishment of our nation: Witnesses at the Creation by Richard B. Morris tells the story of John Jay, Alexander Hamilton, and James Madison as they pushed for the adoption of the Constitution; Founding Brothers: The Revolutionary Generation by Joseph J. Ellis uses a series of vignettes to illumine Madison, Hamilton, Burr, Washington, Adams, Franklin, Jefferson and their times. Within the last year I have learned from A Leap in the Dark: The Struggle to Create the American Republic by John Ferling, and from 46 Pages: Thomas Paine, Common Sense, and the Turning Point to Independence by Scott Liell.

Perhaps, though, the book which moved me most was Nothing but Victory: The Army of the Tennessee, 1861-1865 by Steven E. Woodworth, a brilliant account of the major army of the west in the Civil War. The courage, endurance, and sacrifice of the men who fought for the Union beggar description. The writing is brilliant. An excerpt :

". . . The time was about 6pm, and the first day's battle at Shiloh was over. As the guns fell silent, somewhere along the Union line a band struck up ' The Star-Spangled Banner.'
It had been a beautiful spring day, and some men had complained of the heat. That night, however, a cold rain poured down in torrents. The cabin Grant had designated as his headquarters was in use by a surgeon diligently amputating and tossing the severed limbs out a window to join a growing pile outside. The steamboats at the landing were likewise full of wounded men. So the commanding general fared as his soldiers did, without shelter under the pitiless downpour.
Sherman found him that night, standing under the scant shelter of a tree lantern in one hand, smoking a cigar. "Well, Grant,' Sherman quipped, 'we've had the devil's own day, haven't we?'
'Yes,' Grant replied between puffs on his cigar. 'Lick 'em tomorrow, though.'"