William John Kowalski III is a dual citizen American-Canadian novelist and screenwriter, born on August 3, 1970. He is best known for his debut novel, Eddie’s Bastard (1999). His other notable works include Somewhere South of Here, The Adventures of Flash Jackson, The Good Neighbor, and The Hundred Hearts, the latter of which won the Thomas Raddall Atlantic Fiction Award.

Kowalski has made significant contributions to adult literacy, with short novels published by Orca Book Publishers, including The Barrio Kings and Something Noble. His literature has been translated into over fifteen languages. A graduate of St. John's College, Kowalski has cited influences ranging from Ernest Hemingway to Gabriel García Márquez.

In addition to writing, Kowalski is an active member of the literary community. He serves as a board member of PEN Canada and is a former chair of the Canadian Issues Committee. Kowalski is also an adult educator, instructional designer, and blogger, known for his advocacy of free speech.