Hanley coauthored the Blackwell Guide to the Philosophy of Language (ISBN 0-6312-3142-0)
He has written on philosophy in fiction. He is the author of the book, Is Data Human? The Metaphysics of Star Trek (ISBN 0-465-09124-5), which explores a number of philosophical questions raised by various episodes of Star Trek: The Next Generation, Star Trek: Deep Space Nine, and Star Trek: Voyager, such as whether Data is human, and whether a character called Tuvix, temporarily formed by the characters Tuvok and Neelix being beamed into a single body, was a separate being entitled to its own existence.
While the title of the book was changed to Is Data Human? The Metaphysics of Star Trek for the paperback version, the original hardcover version of the same book was simply entitled, The Metaphysics of Star Trek.
Hanley is frequently critical of the Star Trek writers' sophistication in treating philosophical issues, but nevertheless praises Star Trek for its willingness, rare among TV shows, to frequently raise questions of philosophical significance. According to WorldCat, the book is held in almost 800 libraries.[1]
He is also the editor of South Park and Philosophy: Bigger, Longer, and More Penetrating (ISBN 0-8126-9613-1), released 28 March 2007.[2]