The narrator is a mild, unambitious Wall Street lawyer with a quiet practice in other people's property and an office staffed by Turkey, who is no use after noon, and Nippers, who is no use before it. He hires a third copyist, Bartleby, who works beautifully for two days and then begins declining, mildly and without argument and without leaving, to do anything else he is asked, until the lawyer has offered him twenty dollars to go and finally moved his own firm out of the building. Melville plays it as office farce and then takes the floor away. Forty minutes, and he never explains his man.
Bartleby the Scrivener is 14,457 words. At an average adult reading pace of 300 words a minute that is about 48 min, or roughly 36 min if you read quickly and 1 hr 12 min at a more deliberate 200 words a minute.
That count is measured from the complete public-domain text rather than estimated from a page count, so you can compare all the books side by side.