What is the fine-grained topic of the following text: “The self-published picture book The Rabbit Who Wants to Fall Asleep, by Carl-Johan Forssén Ehrlin, sold more than 29,000 print copies at outlets that report to Nielsen BookScan last week, making it the #2 juvenile fiction title for the week ended August 23. Only return the topic.
The sales success of the self-published picture book The Rabbit Who Wants to Fall Asleep.