Baarn, the artist, 1946. Single leaf, printed on one side (8.0 x 6.0 mm). Woodcut, Monogrammed 'MCE'.

The world-famous Dutch artist Maurits Cornelis Escher (1898-1972) created several bookplates. One of the rarer ones was made for his neighbour, the engineer, mathematics teacher and amateur astronomer Albert Ernst Bosman (1891-1961). Bosman later put Escher into contact with the mathematician Hans de Rijk, who, under the pseudonym of Bruno Ernst, wrote several books popularizing Escher's then little-known works. Bosman is also known as the inventor of the Pythagoras tree. "The Pythagoras tree is a plane fractal constructed from squares. Invented by the Dutch mathematics teacher Albert E. Bosman in 1942. It is named after the ancient Greek mathematician Pythagoras because each triple of touching squares encloses a right triangle, in a configuration traditionally used to depict the Pythagorean theorem. If the largest square has a size of L × L, the entire Pythagoras tree fits snugly inside a box of size 6L × 4L" (Wikipedia). It may have been Bosman who directed Escher towards the research of fractals. Escher had been interested in infinities, but struggled with finding a way to depict infinity. His first successful attempts were made after becoming friends with Bosman. The Bosman bookplate shows a 'bookworm' (actually a caterpillar) crawling over an open book. An excellent, clean copy. Bool 347.