Thump, Thump, Rat-a-tat tat by Gene Baer showed up on several toddler-friendly book lists. It seems like this is the only picture book Gene Baer wrote.
There is no storyline- the book portrays the sound that a marching band makes as it gets progressively closer and then further away. The size of the words and the illustrations match the crescendo and decrescendo of the music. Lois Elhert did the bold geometric illustrations that match the storyline perfectly. The rhythm of the text is very soothing and appealing for toddlers. Jonathan had a lot of fun with this book- especially marching in time with the rhythm of the words. This book is very cleverly written and illustrated, and would be a great resource for talking about sound. It's a shame that Baer didn't write more children's picture books!