Edward Henry "Harry" Greb (June 6, 1894 – October 22, 1926) was an American professional boxer. He was the World Middleweight Champion from 1923 to 1926 and the American Light Heavyweight Champion from 1922 to 1923. He fought a recorded 303 times in his 13 year-career, against the best opposition the talent-rich 1910s & 20s could provide him, frequently squaring off against light heavyweights and even heavyweights. Widely considered one of the best fighters of all time, Greb was named the 7th greatest fighter of the past 80 years by The Ring Magazine, the 5th greatest fighter of all-time by historian Bert Sugar and ranked as the #1 middleweight and the #2 pound-for-pound fighter of all-time by the International Boxing Research Organization.

He had a highly aggressive, very fast, swarming style of fighting and buried his opponents under a blizzard of punches. Greb was also a master at dirty fighting and had no qualms about employing all manner of dubious tactics, such as spinning his opponent and using the heel and laces of his gloves. Greb often got as much as he gave and unbeknownst to the press continued to fight a number of matches even as he became blind in one eye, due to an injury suffered in an earlier match. The 'Pittsburgh Windmill' was also very durable, suffering only 2 TKO losses. The first was in his seventh bout and the second happened 3 years later when Greb broke the radius of his left arm. Greb finished the round but was unable to continue the fight. The second was in a bout where Greb was heavily outweighed.