When City Dog arrives for a visit to the country in springtime, he heads off for a gleeful leash-free run and encounters Country Frog. When asked why he is sitting on a rock, Country Frog replies that he is waiting for a friend, but that City Dog will do. Thus begins a friendship that lasts through the seasons.
Picture books of friendship don't come much more poignant than this. Mo Willems is a master of subtly injecting emotion into the play of words and images in his books, and combining his words with Jon J. Muth's expressive watercolour illustrations is a match made in heaven. The colours capture the essence of the four seasons and the animals have obvious personalities. City Dog's tail and ears are consistently perfect, and in the image below his confusion at Country Frog's absence is evident. The illustrations extend Willems' carefully selected words and, in keeping with the origins of the word, beautifully illuminate them.