Stanislaus Joyce retained a separate portion of the manuscript which include a self-contained episode that would later be developed into a scene in A Portrait of the Artist as a Young Man: This section was later rediscovered and published in 1955.

[8][9] Joyce introduced the concept of “epiphany” in Stephen Hero to preface a discussion of Thomas Aquinas’s three criteria of beauty, wholeness, harmony, and radiance: when the object “seems to us radiant, [it] achieves its epiphany.” [10] The term isn’t used when Stephen Dedalus covers the same ground in A Portrait of the Artist as a Young Man.

Editor Theodore Spencer wrote in his introduction to the published edition of the manuscript that only in Stephen Hero does Joyce explicate an esthetic theory that pervades all of his other works.

[11] He points to the following passage: Stephen as he passed on his quest heard the following fragment of colloquy out of which he received an impression keen enough to afflict his sensitiveness very severely.…This triviality made him think of collecting many such moments together in a book of epiphanies.

[16] She has also identified four distinct epiphany techniques in Joyce's work, noting their use in Ulysses, from the simplest device, such as the revelation of Gerty Macdowell's limp, to the more complex, such as the bowl symbolism in "Telemachus".

[17] Australian scholar S. L. Goldberg has argued that interior monologue in Ulysses is rooted in Joyce's epiphany technique.