Evolution of Backhand Grips From Wikipedia
The evolution of backhand grips
The backhand can be executed with either one or both hands. For most of the 20th century it was performed with one hand, using either a backhand Eastern or Continental grip. In modern tennis, there are a few professional players who use a Western one-hand backhand. This shot is held in a similar manner to the Eastern forehand. It has much more topspin potential than the traditional Eastern one-hander. The Western one-handed backhand grip makes it easier for a one-handed player to hit balls at shoulder height, but harder to hit low balls, and vice versa for the eastern one-handed backhand. The eastern one-handed backhand and its variants are used by most pros with strong single-handed backhand drives, like Gustavo Kuerten, especially Richard Gasquet among the men, and Justine Heninamong the women.
The two-handed backhand is most commonly used with the forehand hand holding the racquet with a Continental grip and the non-dominant hand holding the racquet with an Semi-western forehand grip. While this is by far the most common way to hit a two-handed backhand, there are players who use different ways of holding the racquet for a two-handed backhand.
The player long considered to have had the best backhand of all time, Don Budge, had a very powerful one-handed stroke in the 1930s and 1940s that imparted topspin onto the ball. Ken Rosewall, a one-handed backhand, used a tremendously accurate slice backhand with underspin through the 1950s and 1960s. The one-handed backhand slice is often used in rallies as it is a comfortable shot. Andre Agassi in particular increased his use of the one-handed backhand and often hit an unreturnable dropshot with it.