Explain SMBC — the wiki for Saturday Morning Breakfast Cereal

This comic is not a traditional strip but rather an advertisement or announcement for "Bobby and the Gurg: An illustrated book for sober-minded children," with a prompt to "click here to download." This was apparently a side project or bonus content by SMBC creator Zach Weinersmith, presented as an illustrated children's book aimed at "sober-minded children" -- a humorous qualifier suggesting the book's content is more intellectually rigorous or darkly realistic than typical children's fare.

The votey panel shows a man praying: "Dear Voltaire's ghost, please let everyone recognize this as irony." This suggests the book's content is satirical or ironic in nature, and Weinersmith is humorously worried that readers might take it at face value. The prayer is directed to Voltaire's ghost rather than God, which is itself a joke -- Voltaire being the famous Enlightenment satirist who would presumably be the patron saint of recognizing irony.