The Very Lonely Firefly by Eric Carle (ages 3-6)

Young readers empathize with the lonely firefly as he looks for a group where he will really “belong.” In his search for compatible companions, he meets many other night creatures, but none is quite right—until the happy surprise at the very end when the illustration of a swarm of friendly fireflies literally shines and twinkles a welcome in the night. Heartwarming.