Garry Trudeau was assisted by inker Don Carlton (Alter 1990, 66). There was a transition during the early 1970s in the lettering of the strip. After about a year (apparently ending in early 1973) during which Trudeau lettered the strip and Carlton inked it, Trudeau delegated the lettering to Carlton, who then remained for decades as inker and letterer of the strip (Walker 2010, 30–31). GCD’s credits reflect that the time period covered by this volume appears to begin during the time that Trudeau lettered and Carlton inked, and end during the time that Carlton inked and lettered.
__________
References:
Alter, Jonathan. 1990. “Real Life with Garry Trudeau.” Newsweek, October 15. Microfilm.
Walker, Brian. 2010. Doonesbury and the Art of G. B. Trudeau. New Haven: Yale University Press.