The possibilities in form throughout one poetry collection feel unimaginably wide. But consistency of form can reveal the true beauty of language, particularly for readers who are otherwise disinclined toward the medium. Jim Tilley’s new collection, When Godot Arrived (Red Hen Press; 104 pages) offers eighty-one free-verse sonnets with big ideas that move fluidly between the natural world and the world of mathematics to explore larger themes of fatherhood, mortality, and a fractured world that often feels hopeless. It’s a collection personal and observational, aided by an assertive voice leaning heavily into a form he’s mastered.