Walk along Oude Delft, the canal that may be the oldest in the Netherlands, and you pass number 203: a stately townhouse with a copper-trimmed facade that looks much as it did when an Italian architect named Bollina designed it in 1750. Inside, a 40-meter corridor runs the length of the building beneath ceilings worked in Louis XIV stucco. In the nineteenth century the house belonged to a succession of prominent Delft families. In 1886 it was sold to the Roman Catholic charity for the poor, then to the St. Hippolytus Foundation, which used it first as a home for the elderly and then as a hospital until 1970. In 1983, a young architecture practice without quite enough money rented part of it. Mecanoo now occupies the entire building, drafting plans for libraries in Birmingham and Tainan from rooms where almshouse residents once lived.

Francine Houben, who remains creative director after the four other founders departed between 1988 and 2003, talks about People, Place, Purpose as the firm's working philosophy. The libraries make the case better than any manifesto. The TU Delft Library opened in 1997, integrated with a grassed slope that visitors can walk up to the roof. The Library of Birmingham, completed in 2013 and integrated with the Birmingham Repertory Theatre, wraps its facade in interlocking metallic rings. The LocHal in Tilburg, opened in 2019, transformed a former Dutch Railways locomotive workshop into a public library where the original industrial trusses still arch above the reading floors. In 2020 came the Martin Luther King Jr. Memorial Library renovation in Washington, the District's central library reimagined by a Delft firm whose founders once told a competition jury about a zoo.

Of the five founders, only Houben remains. Henk Doll, Roelf Steenhuis, Erick van Egeraat and Chris de Weijer all departed between 1988 and 2003, scattering in different directions and in some cases starting rival firms. Van Egeraat in particular went on to make his own name as a designer of provocative buildings across Eastern Europe. The breakup happened gradually, partner by partner, the way these things often do, with the firm continuing to take commissions throughout. Houben, who had been the youngest of the founding five, became the sole creative voice. She has since written books with titles like Composition, Contrast, Complexity and Dutch Mountains, the latter a meditation on how a flat country might still produce buildings that feel like landscapes.

The firm now operates from offices in Delft, London, New York and Kaohsiung. The Kaohsiung outpost matters more than its size suggests: Mecanoo designed the National Kaohsiung Center for the Arts, which opened in 2018. Other recent and current work spans the New York Public Library's Midtown renovation, the European Investment Bank in Luxembourg, the Natural History Museum in Abu Dhabi, and Kaohsiung Station itself. The work hops between continents, but the postcard always returns to Oude Delft 203. There, on a canal that may be the oldest in the Netherlands, a firm named after a children's toy keeps designing buildings the size of small towns.