The artist Anna Cassel (1860–1937) has until now been known for her paintings of magnificent natural views, landscapes and urban environments. However, the fact that her artistry also reflected spiritual beliefs and her involvement in, among other things, spiritualism and theosophy has not been noticed. Only now, nearly a century after her death, is Anna Cassel's significance for abstract and spiritual art beginning to shine through, not least thanks to her deep friendship and collaboration with fellow artist Hilma af Klint. In this book, this side of Anna Cassels is presented for the first time to a wider audience together with a vivid description of her role in the circle of spiritually searching artists active around the turn of the century.