In 1918, Dutch architect and furniture designer Gerrit Rietveld developed the first iteration of his influential Red Blue Chair. A member of the de Stijl art and architecture movement, which espoused the belief that a post-World War I Europe could restore itself culturally using new, simplified forms and pure abstraction, Rietveld defied several furniture making conventions with his new design. Red Blue Chair stripped the traditional lounge chair of its volume, reducing the form to a series of rectangular wooden planes as a means to create physical and visual balance. Rietveld’s instructions for building the chair instruct its maker to print the following verse (translated from German), from author and poet Christian Morgenstern’s poem Der Aesthet, and to attach it under the seat: “When I sit, I do not want / to sit like my seat-flesh likes / but rather like my seat-mind would, / if he were sitting, weave the chair for himself.”

Essential to this pioneering silhouette was the inclusion of a new type of joint used to link the pieces. Defying Western joinery traditions, in which points of connection are typically concealed within a given form, Rietveld’s joint placed these junctions front and center. Using three overlapping battens in three right-angled directions, Rietveld made his joints even more conspicuous by extending each piece beyond the point of intersection. By magnifying these oft-hidden details, Rietveld forged a new transparency in design—and spotlighted joinery as a medium for creativity and innovation that deserved to be celebrated.

More than a century later, the subject of physical points of connection receives its due commemoration with U-Joints: A Taxonomy of Connections, an independently-published compendium from architect Andrea Caputo and design professor Anniina Koivu, who served as editors, that encourages readers to look more closely at the details of design. Through six chapters and more than 900 pages, the hefty book traverses the subcategories of joinery with a vast taxonomy for each, fleshing out mechanical joints, knots, adhesives, sealants, welded points, and beyond. These encyclopedic surveys are presented alongside essays, interviews, anecdotes, and photographic studies from an international group of more than 120 architects, designers, artists, inventors, and scholars, demonstrating the cultural, social, and artistic story of the world’s omnipresent, yet overlooked, structural connectors.