Ian P. Howard is Professor at the Centre for Vision Research at York University in Toronto. He is the co-author of several books including Human Spatial Organization, Human Visual Organization, and with Brian J. Rogers, of Binocular Vision and Stereopsis (Oxford University Press, 1995), as well as Seeing in Depth, (Porteous and Oxford University Press, 2005). Brain J. Rogers is Professor of Experimental Psychology at Oxford University. He is the author, with Ian P. Howard, of Binocular Vision and Stereopsis, OUP, 1995 and Seeing in Depth, I Porteous and OUP, 2005.