In spring 2023 the Seattle Art Museum announced that patrons Jon and Kim Shirley had generously gifted the Shirley Family Collection to the museum. The collection--one of the most important private holdings of Alexander Calder's art--is the result of thirty-five years of thoughtful acquisitions and features many significant examples from his production. It comprises more than forty-five artworks representing every decade of the artist's career, including superlative examples of his wire sculptures, hanging mobiles, and stationary stabiles dating from the 1920s to the 1970s. This richly illustrated publication accompanies SAM's inaugural exhibition of works from the collection, demonstrating Calder's unique vision, which has had a profound influence on contemporary culture. It features a curatorial foreword by José Carlos Diaz; short essays by Jon Shirley tracing his evolution as a passionate and informed collector of Calder's work and discussing the importance of scale in the artist's sculpture, which ranges from the miniature to the monumental; and an essay by art historian Elizabeth Hutton Turner that expands on the artist's life and his extraordinary impact on twentieth-century art. Short contributions by Alexander S. C. Rower, president of the Calder Foundation and grandson of the artist, focus on ten of the collection's artworks, situating them within Calder's oeuvre.