Conversation so far:
Was Robert Todd Carroll a writer?
Robert Todd Carroll authored Becoming a Critical Thinker, a textbook for introductory logic and critical thinking courses.
What was Becoming a Critical Thinker about?
It covers subjects such as language and critical thinking, the mass media and other sources of information, fallacies of reasoning, and inductive and deductive arguments.
Did Robert Todd Carroll write anything else?
Robert Todd Carroll achieved notability by publishing The Skeptic's Dictionary online in 1994. It is the print version of the website skepdic.com.

Question: What was that about?
Self-contained rewrite: What was Robert Todd Carroll's The Skeptic's Dictionary about?