At an early age, Hilma af Klint developed an interest in spiritualism a religious inclination and philosophical outlook that constituted an important part of the European zeitgeist in the second half of the nineteenth century. Together with four other women she was part of the group The Five. The members of the group acted as mediums and believed that they received messages from the spirit world. In this first volume of Hilma af Klints Catalogue Raisonné, the fifteen sketchbooks they produced during the years 1895 to 1910 are presented. Together they constitute an important starting point for Hilma af Klints abstract painting and provide a background to what would later lead to her most important series: The Paintings for the Temple.