Henri Matisse (1869-1954) is adored worldwide as a revolutionary painter and loved for his collages, or papiers découpés, the icons of his late work. His paintings and drawings for a long time overshadowed his achievements as a sculptor. Yet his Back Series, four bas-reliefs showing a nude, created between 1908 and 1930, are widely recognised as a milestone in modern sculpture. Starting out from the naturalistic depiction, Matisse gradually transformed it to reach a radically abstracted figure. Each of the four original plaster casts represents a decisive moment of this artistic process. This transformative process has parallels in Matisse's painting and drawing. Published in conjunction with a major exhibition at Kunsthaus Zürich marking the artist's 150th anniversary, this is the first book to explore the relation between metamorphosis and feedback in both main fields of the artist's work. Documents of his diverse sources of inspiration for his sculptures - photographs of nudes, examples from African and ancient art - as well as images featuring Matisse at work as sculptor, round out this volume. It is a welcome addition to any art library, highlighting the lesser known side of this modern master. Published to coincide with the exhibitions 'Matisse - Metamorphoses' at the Kunsthaus, Zürich between 30 August and 8 December 2019, and 'Musée Matisse', in Nice between 15 February and 15 May 2020.