From Amazon.com:

SERVICE TO FIVE PRESIDENTS

Fifty years of service at the White House in various capacities, including bodyguard to Lincoln, William H. Crook's memoir brings an astonishing array of personal details of life in the executive mansion. His sensitive observations of Lincoln are especially moving.

A well-known figure in Washington, Crook knew every president from Lincoln until Crook's death in 1915. He was a keen observer and his stories will entertain and sometimes surprise you.