On the one hand, the work of Lucerne artist Hans Erni, who died in 2015 at the age of 106, is rather impressive, not least due to its enormous variety of materials: painting in small and monumental format, drawing and printmaking, ceramics and relief, poster and book art. On the other hand, this wealth corresponds to his stylistic range: from realistic and cubist-inspired beginnings during the 1930's, to purely abstract compositions, and the virtuoso synthesis of the two forms of expression in the 1940's. Erni’s impressive contributions to surrealism, with their combination of informal background and masterly figurative representation, lay the ground for his works of the subsequent decades. After previously being politically reviled, he now realizes numerous public works and has become internationally known as one of the most important representatives of Swiss art in the 20th century. His ever-keen interest in social, political, and environmental matters, and his commitment to peace, social justice, and nature conservation are all reflected in his visual and graphic work, as well as his curiosity about foreign cultures. This publication on the occasion of the 40th anniversary of the Hans Erni Museum provides an overview of the diversified collection of the Hans Erni Foundation.