The pages of Great BooJ(s of the Western World are printed in either one or two columns. The upper and lower halves of a one-column page are indicated by the letters a and b. When the text is printed in two columns, the letters a and b refer to the upper and lower halves of the lefthand column, the letters c and d to the upper and lower halves of the right-hand column. These half and quarter page sections are based on divisions of a full text page.