Stefan Knapp, born in Biłgoraj, Poland in 1921, was a painter and sculptor, best known for developing and patenting a technique of painting with enamel paint on steel which facilitated the decoration of public architectural structures.


In 1935, he began studies at the Lwów Polytechnic, but they were cut short when the outbreak of World War II saw the Soviet Union occupy Lwów, murder Knapp's father and send Stefan to a gulag in Siberia. While in the Gulag, despite artistic endeavors being limited, Knapp made chess sets out of bread and playing cards out of trash for his fellow prisoners.

He was released in 1942, after the Sikorski-Mayski Agreement was signed between Poland and Soviet Union. He joined the Anders Army and volunteered for the air force, finding himself being sent to Great Britain where he served as an officer and Spitfire pilot in the Royal Air Force. While in the RAF, Knapp pursued his art by painting or sketching portraits of his fellow pilots in 318 Squadron. After the end of the war he remained in London and took advantage of a veteran's stipend to further his studies at the Royal Academy and at the Slade School of Fine Art.


His experience in the Gulag and as an RAF pilot caused him to suffer from recurring nightmares and insomnia for many years. Consequently, he used his art as a form of therapy. In the late 1940’s, this resulted in a series of works titled Gulag that were noted for many experimental techniques.


Knapp was known for producing murals of unprecedented size with materials which were intended to last for thousands of years. He first received wide attention and acclaim during his exhibition in London in 1954, where he presented a unique and innovative style and technique, which involved melting glass into pieces of light steel, using specially made furnaces.


In the late 1950’s, Knapp moved away from traditional painting to experiment with enamel and sculpture. In the 1960’s, he painted several murals at Heathrow Airport, which were later reinstalled in the 1990’s. In the early 1950’s, he painted a mural in the foyer of Hallfield Primary School, Westminster which was designed by the architect Denys Lasdun. He also painted a mural for the Warsaw metro entitled The Battle of Britain. Between 1954-1968, he held at least one exhibition each year, including ones in the Netherlands, Austria, and Peru. Knapp also designed many decorations for synagogues, many of which he based on his memories of synagogues, kirkuts and Jewish prayer houses in his childhood town of Biłgoraj. In the 1970’s, Knapp and his wife moved to the British countryside, where he built his own furnace to accommodate the scale of his work. Knapp is also the author of the largest mural in the world, sized about 60⨯15 metres, painted on the Alexander's department store building in Paramus, New Jersey. The building has since been demolished and the mural is currently in storage.