Peadar Ó Guilín is the author of the YA novel, The Call, inspired by the beautiful northwest of Ireland where he grew up. The Invasion, a sequel to The Call and the end of the duology, was published in March 2018.

In September 2007, Peadar published his first novel, The Inferior, which the Times Educational Supplement called "a stark, dark tale, written with great energy and confidence and some arresting reflections on human nature." Foreign editors liked it too, and over the following year it was translated into eight languages, including Japanese and Korean.

His fantasy and SF short stories have appeared in numerous venues, including Black Gate magazine and an anthology celebrating the best of the iconic Weird Tales.