Dr. Karl Prusik (born 19 May 1896 in Vienna; d. 8 May 1961 in Perchtoldsdorf bei Wien) (also spelled Prussik) was an Austrian mountaineer, with Czech origins, who is known as the inventor of the prusik knot. He died in May 1961 at the age of 65.
The benefit of the knot is that, when weighted, it grips the rope that it is tied around. When the weight is removed, it is free to slide. This enables it to be used in a number of self rescue situations or for ascending a rope. The knot is also seen spelled incorrectly as prussic.
Prusik served twice as president of the Austrian Alpine Club (OeAV), and is credited with pioneering over 70 new ascents and routes.
After the Anschluss, Prusik was one of the supporters of the then Nazi German Alpine Club (German: Deutscher Alpenverein) led by Arthur Seyss-Inquart. In 1941, aged 45 years, he was called up for service as a lieutenant in the German Wehrmacht. In 1942, he was promoted to captain and received the War Merit Cross, 2nd class, awarded for operations behind the front.
In 1947, Karl Prusik returned from captivity and became the first vice president of the Österreichischer Alpenklub (ÖAK).