Author: Apathetic Star
Date: April 15, 2015
A strip of torn envelope peeped from under the dimpled pillow. In the act of going he stayed to straighten the bedspread. — Who was the letter from? he asked. Bold hand. Marion. — O, Boylan, she said
[Spoiler Alert] We later learn that Blazes Boylan is a man with whom Molly is having an affair, hence the attempt to hide the letter out of sight and brush it off as a work-related matter - even though Bloom already knows about the extra-marital relations. He himself is also engaged in a (solely) epistolary affair with a woman named Martha Clifford, whose letter to Bloom we see in the next chapter. This marks an instance that slips by, but it actually contains a lot of information on the upcoming narrative and insight into the Blooms' marriage.