David Gilmour’s book “Sparrow Nights” is about Darius Halloway, a French literature professor and a connoisseur of wine, women, and ideas. After his fiancée Emma breaks up with him, Darius starts to feel depressed and sleep-deprived. He starts to plan a complex retaliation as he struggles with his loss, which puts him in a dangerous position. The book is a fascinating investigation of seductive and psychotic extremes.