The book Nick is reading is Winesburg, Ohio by Sherwood Anderson, which features a prologue titled "The Book of the Grotesque." "Grotesque" being the title of this episode.
The first episode since the Pilot (2015) (Rubén Blades (Daniel Salazar) and Mercedes Mason (Ofelia Salazar) did not appear until late in episode 2) that does not feature all of the main cast members. Many of them get "credit only" billing.
This is an unusual (at the time) episode in the series in that it focuses entirely on just one character, in this case, Nick. (Madison makes a brief appearance in a flashback.) This was a tactic the show would adopt more fully from Season 6 on, following criticism that the cast was just too diffuse and that it was hard to get a handle on any of the characters as there were simply too many of them.
Lexi Johnson returns to the show to reprise her role as Gloria, Nick's fellow addict and the first walker we encountered in the show.