Printing errors have been discovered in Figures 1.2 and 1.3. Labels on the vertical axis are reversed in Figure 1.2, and one label (“Large”) is missing in Figure 1.3. I hope that the context makes it clear that these are errors and that readers have not been confused.

These errors are being corrected in the e-book. Those who have purchased the e-book through the University of Toronto Press may request a corrected version.