After establishing herself as an award-caliber young star as Helen Keller in both the original stage and screen versions of "The Miracle Worker," Duke conquered television in dual roles as (per the famous theme song) "cousins, identical cousins" Patty and Cathy in this classic mid-1960s sitcom created by best-selling author Sidney Sheldon.

The star clearly has fun playing two vastly different characters, one as mischievous as the other is strait-laced, and it's also fun to watch her essentially act opposite herself.

William Schallert and Jean Byron play the fictional Patty's parents. DVD extra: retrospective documentary. *** (Not rated)

Buy 'The Patty Duke Show' Season One on DVD.