“Lerner [is] among the most promising young poets now writing.”—Publishers Weekly“Sharp, ambitious, and impressive.” —Boston ReviewNational Book Award finalist Ben Lerner turns to science once again for his guiding metaphor. “Mean free path” is the average distance a particle travels before colliding with another particle. The poems in Lerner’s third collection are full of layered collisions—repetitions, fragmentations, stutters, re-combinations—that track how language threatens to break up or change course under the emotional pressures of the utterance. And then there’s the larger collision of love, and while Lerner questions whether love poems are even possible, he composes a gorgeous, symphonic, and complicated one.You startled me. I thought you were sleepingIn the traditional sense. I like lookingAt anything under glass, especiallyGlass. You called me. Like overheardDreams. I’m writing this one as a womanComfortable with failure. I promise I will neverBut the predicate withered. If you areUncomfortable seeing this as portraitureClose your eyes. No, you startledBen Lerner is the author of three books of poetry and was named a finalist for the National Book Award for his second book, Angle of Yaw. He holds degrees from Brown University, co-founded No: a journal of the arts, and teaches at the University of Pittsburgh.