Muth (Come On, Rain!) recasts a short story by Tolstoy into picture-book format, substituting a boy and his animal friends for the czar and his human companions. Yearning to be a good person, Nikolai asks, "When is the best time to do things? Who is the most important one? What is the right thing to do?" Sonya the heron, Gogol the monkey and Pushkin the dog offer their opinions, but their answers do not satisfy Nikolai. He visits Leo, an old turtle who lives in the mountains. While there, he helps Leo with his garden and rescues an injured panda and her cub, and in so doing, finds the answers he seeks. As Leo explains, "There is only one important time, and that time is now. The most important one is always the one you are with. And the most important thing is to do good for the one who is standing at your side." Moral without being moralistic, the tale sends a simple and direct message unfreighted by pomp or pedantry. Muth's art is as carefully distilled as his prose. A series of misty, evocative watercolors in muted tones suggests the figures and their changing relationships to the landscape. Judicious flashes of color quicken the compositions, as in the red of Nikolai's kite (the kite, released at the end, takes on symbolic value). An afterword describes Tolstoy and his work. Ages 6-up. (Apr.)