When Diane Aziz drives her oldest son, Walter, from Los Angeles to college at UC Berkeley, it will be her last parental act before falling into a deep depression. When she enters a state hospital, her closest friend tries to keep the children safe and their mother's dreams for them alive.

At Berkeley, Walter discovers a passion for architecture just as he realizes his life as a student may need to end for lack of funds. Back home in LA, his sister, Lina, watches her classmates prepare for Ivy league schools, and wants to go east with them. And Donny, the little brother everybody loves, begins to hide in plain sight, coding, gaming, and drifting towards a life on the beach, where he falls into an escalating relationship with drugs.

Moving from Berkeley and Los Angeles to New York and back again, this is a story about one family trying to navigate the crisis of their lives. With Commitment, Mona Simpson has written an important and unforgettable novel.