His first book, a collection of science fiction short stories titled Illumined Black, was published by Phantom Press Publications in 1995, when Tonnies was in college. It carried a cover blurb by Bruce Sterling and was positively reviewed in Booklist. His second book, After the Martian Apocalypse, was published by Simon & Schuster in 2004. His third book, The Cryptoterrestrials, was published posthumously by Anomalist Books in 2010.

In 2007 the play Doing Time, which he co-wrote with Canadian filmmaker Paul Kimball (who was working on a documentary about Tonnies), premiered in Halifax, Nova Scotia. He also appeared in the documentary Best Evidence: Top 10 UFO Sightings, and an episode of the Canadian television series Supernatural Investigator.

He appeared on Coast to Coast AM in September 2009., and was a frequent guest on The Paracast.

In November, 2012, Redstar Books published the first volume of Posthuman Blues, which contains excerpts from Tonnies’ long-running blog of the same name. In the introduction, historian Aaron John Gulyas writes that, “Posthuman Blues is of a piece with the Lost Generation of the 1920s and the Beat Generation of the 1950s. Tonnies spoke for his generation with passion, eloquence, and a rare insight.”