This first book by Mary Little, a New York children's librarian, is appropriately set in a New York library which caters mostly to Puerto Rican children. Her hero, Ricardo, an inquisitive mouse, lives near by and is fond of browsing through the shelves and card catalogues. When one day the children decide to do a puppet play about a mouse, Ricardo is naturally concerned, and distressed to find that the children have omitted whiskers from their mouse character. This insult he will not endure and he decides to take militant action against the puppets. This precipitant step almost costs the lives of many mice, but in the end a chastened Ricardo comes to terms with the puppeteers.