The author links Chaucers writings with the medieval optical tradition in its various forms scholastic texts encyclopedias exempla vernacular poetry both in general cultural terms and through the discussion of specific examples. He shows how the science of optics or perspectiva provides an account of spatial perception including visual error and demonstrates how these aspects of optical theory impact on Chaucers poetry. He provides detailed and sustained analysis of the spatial content of narratives across the range of Chaucers works relating them to optical ideas and making use of Lefebvres theory of the production of space. The texts discussed include the Book of the Duchess House of Fame Knights Tale Millers Tale Reeves Tale Merchants Tale Squires Tale and Troilus and Criseyde.