[5] He specialises in hard science fiction stories with mathematical and quantum ontology themes, including the nature of consciousness.

Other themes include genetics, simulated reality, posthumanism, mind uploading, sexuality, artificial intelligence, and the superiority of rational naturalism to religion.

Egan's short stories have been published in a variety of genre magazines, including regular appearances in Interzone and Asimov's Science Fiction.

On 27 February 2019, using ideas developed by Robin Houston and others, Egan produced a superpermutation of seven symbols of length 5906, breaking previous records.

[12] Egan does not attend science fiction conventions,[13] does not sign books, and has stated that he appears in no photographs on the web,[14] though both SF fan sites and Google Search have at times mistakenly identified him as the subject of photos of other people with the same name.