for Apt. 3 by Ezra Jack Keats
In his apartment in the city, Sam hears voices, barking dogs, snoring, and all kinds of other noises. One rainy day he also hears the sad sounds of a harmonica, and wonders who's playing. Sam's search leads him to Apt. 3, where he finds not only the source of the music--but a new friend.
Publisher description retrieved from Google Books.