A field of advice columns that lob texts at people’s troubles has flowered recently, from the Times’ “Match Book” to Lit Hub’s “Dear Book Therapist” to the Paris Review Daily’s “Poetry Rx.” The series run the gamut from straightforward recommendation engines (ask for a thriller, receive a thriller) to columns that see books not as frigates or loaded gunsbut as medicine, selected from the canon’s well-lit pharmacy by a critic in a smock.