A young child and grandfather have a conversation about death.When Grandpa suggests that a caterpillar might die if Christopher puts it in a jar, Christopher asks some questions about death, beginning with "Are you going to die, Grandpa?" The response: "Someday, sweetheart. But I hope not too soon." (…) Their simple exchange covers a lot of philosophical ground. Grandpa acknowledges no one knows when they will die and that Christopher could die before him, but that the chance is small. Grandpa allows that "no one really knows" what happens after death, but he tells Christopher that some people think of heaven ("a place without sadness or war"), others of rebirth ("each time, you get wiser"), and others of "nothing" ("the same as before you were born"). The pair discusses the whys of death ("dying is part of life"), birth ("to learn all sorts of things"), and feelings of fear or comfort about dying. A concluding letter from Christopher to Grandpa, accompanied by an illustration of Christopher alone, offers the titular analogy about becoming a butterfly. Backmatter offers a brief comment and tips for discussion from a grief therapist. Straightforward, gentle, useful, and engaging.

– Kirkus Reviews