Essays and projects illuminate the nature of error and its creative possibilities for architecture. Architecture never goes entirely according to plan. Every project deviates from its designers' expectations, and wise architects learn to anticipate, mitigate, and sometimes celebrate the errors along the way. Perspecta 46 argues that error is part of architecture's essence: mistranslations, contradictions, happy accidents, and wicked problems pervade our systems of design and building, almost always yielding surprising aberrations. Today, with increasingly complex projects underpinned by layers of computer code, small errors can proliferate rapidly, and the dream of errorless architecture seems more utopian than ever. This issue of Perspecta -- the oldest and most distinguished student-edited architectural journal in America -- considers the challenge of defining error, the difficulty of diagnosing and managing it, and the promise (and peril) of following its lead. Essays and projects illuminate error's ambiguous agency both in reality and in the architectural imagination, covering topics that range from Dante's cosmos of divine justice and Michelangelo's architectural "abuses" to Dada urbanism and the warped skyscrapers of Google Earth.