Continues from Sunday PIX (1949 series) Vol. 1 #1 - Vol. 16 #52.
No price listed but did have subscription rates. PIX volumes follow the academic year from September to August. At some point they abandoned the volume/issue system (one volume per academic year with 52 or 53 weekly issues) for volume/issue/lesson number (one volume per academic year with 4 quarterly issues consisting of 13-14 individual lessons). For indexing purposes, lessons equate to issues. In modern PIX, only the first lesson in a quarter has an indicia with the volume and quarterly issue number. Each lesson has a lesson number. Apparently, some time in the early 2000s, they also dropped the date from each lesson.
By 1990s issues range from a minimum of 25% comics to a maximum of 75%. Became mostly reprint material on the comics from the 1960s onward although new adaptation continue to appear from time to time. Incorporated comics from other Cook publications sometime in the 1950s (What to Do, Boy's World, Girls' Companion). For an excellent and mostly accurate resource visit http://www.christiancomicsinternational.org/series_sundaypix.html