ملف:Henry Wager Halleck - Brady-Handy.jpg

English: Henry Wager Halleck ( January 16, 1815 – January 9, 1872) was a United States Army officer, scholar, and lawyer. A noted expert in military studies, he was known by a nickname that became derogatory, "Old Brains." He was an important participant in the admission of California as a state and became a successful lawyer and land developer. Early in the American Civil War, he was a senior Union Army commander in the Western Theater and then served for almost two years as general-in-chief of all U.S. armies. He was "kicked upstairs" to be chief of staff of the Army when Lt. Gen. Ulysses S. Grant, Halleck's former subordinate in the West, whose battlefield victories did much to advance Halleck's career, replaced him in 1864 as general-in-chief for the remainder of the war.