"I am sometimes asked 'What is your objective' and this I cannot truthfully answer. I work 'from' something rather than 'towards' something. It is a process of discovery." Since 1961, Riley has focused exclusively on seemingly simple geometric forms, such as lines, circles, curves, and squares, arrayed across a surface-whether a canvas, wall, or paper-according to an internal logic. The resulting compositions actively engage the viewer, at times triggering sensations of vibration and movement. In the present selection, Riley advances her Measure by Measure series, her most extensive body of work to date, into a new, darker color palette. Once again, changing the way we look and offering a powerful effect on our eyes. This sense of dynamism was explored to great effect in the artist's earliest black-and-white paintings, which established the basis of her enduring formal vocabulary. In 2020, after visiting her own earlier works at her retrospective exhibition organized by the National Galleries of Scotland, Riley returned to black-and-white lozenges, adjusting the orientation of each shape to create a new visual sensation. In 1967, Riley introduced colour into her work, thus expanding the perceptual and optical possibilities of her compositions. Published on the occasion of the 2021 exhibition at David Zwirner, London, this monograph features new scholarship on the artist by art historian Éric de Chassey, who looks at how Riley's past, as well as previous artists, has led to this body of work.