A shapeless but engaging portrayal of its underachieving protagonist and narrator is the best feature of this bittersweet second novel by Lennon (The Light of Failing Stars, 1997). Unsuccessful artist Tim Mix returns home (Riverbank, New Jersey) for the funeral of his father Carl, a successful cartoonist whose popular “Family Funnies” strip had exploited his own family’s life. And that’s the problem: Carl’s widow Dorothy is in a nursing home suffering from “senile dementia”; their five children all inhibiting guilts and neuroses—notably, Tim’s uptight older brother Bobby and younger brother Pierce, a paranoid schizophrenic who seldom leaves the house. As the Mixes, uh, mix, reestablishing their essential (and mutual) unconcern, Tim contrarily finds himself drawn away from the independence he had created, and back into the orbits of his family and his father’s legacy. He inherits the opportunity to take over “Family Funnies,” and is feted by his hometown at a (hilarious) “Funny Fest” that celebrates Carl Mix’s fame (the town even renames itself “Mixville”). The story charts Tim’s imperfect adjustments to such temptations and distractions, as well as his relationships with Brad Wurster, the choleric artist who tutors him; Ken Dorn, the sinister rival cartoonist who has designs on “Family Funnies”; and Susan Lennon Caletti, his father’s editor, and, just possibly, the new woman in Tim’s life. Overall, it’s an uneven performance: Lennon’s prose (skillfully rendering Tim’s alert, wary sensibility) is witty and observant, studded with odd, often truculent imagery (“She had the long blotchy nose of a border collie and cheeks sunken enough to eat soup out of”), while his characterizations vary from, well, cartoonish to precise and affecting (the destroyed Dorothy and jittery Pierce are especially vivid). Tim Mix’s gradual transformation from passivity to involvement and accomplishment is his story’s wistful core. If you believe in it, you’ll like Lennon’s novel.