This article examines a series of remarkable English drawings penned around 1300 by an anonymous artist in the margins of a manuscript now held by the Walters Art Museum in Baltimore (Walters Book of Hours MS W.102). Rarely studied by art historians, these forty-seven marginalia are strikingly original and call for a new analytical approach if we are to understand their full implications. The method of kinesic analysis is used in this article to account for movement-based aspects in the represented figures. The medieval illuminator who created the marginal imagery of Walters MS W.102 was able to experiment with visual cognition and sensorimotor imagination in drawings that resist the application of traditional iconographic labels.