http://lithub.com/the-man-in-the-macintosh-one-of-literatures-great-mysteries/
..."At every turn, around every corner of Dublins cobblestone streets, in every interaction Leopold Bloom has or avoids, in everything he does and in everything he dreams, as he wanders the city on June 16th, 1904, little gaps open up, and riddles, mysteries, ambiguities tumble out. Amongst this seeming infinity of minute mysteries in the text, there is perhaps no greater mystery than the question of the identity of the so-called man in the macintosh. In the 94 years since the books publication, Joyce scholars have written innumerable words arguing for and against various answers to this question.
But before we get to the attempts at an answer, lets remind ourselves of the enigmas particulars. The man in the macintosh is mentioned or alluded to numerous times throughout the pages of Ulysses. He first appears in the Hades episode, where Bloom attends Dignams funeral with eleven other mourners. Just as the gravediggers are about to lower the coffin into the grave, Bloom notices another presence: Now who is that lankylooking galoot over there in the macintosh? Now who is he Id like to know? Now, Id give a trifle to know who he is. Always someone turns up you never dreamt of. This lankylooking galoots presence, Bloom notes, turns the dozen mourners into a group of 13 (Deaths number, Bloom thinks, even if he admits its a silly superstition).
Where the deuce did he pop out of? Bloom wonders. He wasnt in the chapel, that Ill swear. The ghostly presence, at first, seems like it could possibly all be in Blooms headsince much of the novel plays out in the stream of his consciousnessbut a few pages later, Hynes, a newspaper reporter who had previously appeared in Joyces short story Ivy Day in the Committee Room, and who is writing down the names of the funeral attendees for the purpose of publication in the Telegraph, asks Bloom if he saw that fellow in the, fellow was over there in the
To which Bloom responds, Macintosh. Yes, I saw him. Hynes scribbles down the name MIntosh, because he assumes that Bloom was giving him the mans name rather than describing him by his clothing. Hynes misidentifications, of course, wont end there. Bloom will see his name written in the paper as Boom by days end (next to MIntoshs name, in the Eumeus episode).
In The Wandering Rocks, a few episodes after the Hades funeral procession, we see potentially the same macintoshed man: a pedestrian in a brown macintosh, eating dry bread, passed swiftly and unscathed across the viceroys path. Then, in the Sirens episode, Bloom, under the influence of a sirens song, in one of many chains of free associations, questions: Wonder who was that chap at the grave in the brown mackin. His next mention, in the Cyclops episode, gives us a new clue (or perhaps a misdirection?) when we read, The man in the brown macintosh loves a lady who is dead. What exactly that episodes narrator knows to make him claim that the lankylooking galoot loves a lady who is dead is a mystery within a mystery. In Nausicaa, Bloom once again thinks of that fellow today at the graveside in the brown macintosh and claims he has corns on his kismet. In the Oxen in the Sun episode, the mystery man enters again, and may actually be the one who starts the fire in that chapterespecially since, in the following chapter, the Circe episode, amongst the chaotic phantasmagoria of Nighttown, the man in the macintosh springs up through a trapdoor and points an elongated finger at Bloom, accusing him of being Leopold MIntosh, the notorious fireraiser.
The final mention of the man in the macintosh arrives in the penultimate chapter, the Ithaca episode, which takes the form of a catechism of questions and answers. One question reads: What selfinvolved enigma did Bloom risen, going, gathering multicoloured multiform multitudinous garments, voluntarily apprehending, not comprehend? The answer is tellingly in the form of a question: Who was MIntosh?........"