Original: Dürer made large numbers of preparatory drawings, especially for his paintings and engravings, and many survive, most famously the Praying Hands (1508 Albertina, Vienna), a study for an apostle in the Heller altarpiece.
Simplified: Dürer made large numbers of other practice drawings, especially for his paintings and engravings, and many survive, most famously the Praying Hands (1508 Albertina, Vienna).