So, there is a group of people who really love books and libraries, and they want to make sure that other people love them too! This group is called the Young Adult Library Services Association, or YALSA for short.
YALSA is all about helping young adults, who are usually between the ages of 12 and 18, find books and other things at the library that they will really enjoy. They talk to librarians and teachers and figure out what kinds of books and activities are popular with young adults.
YALSA also gives out awards to authors who write really great books for young adults. They have different awards, like the Michael L. Printz Award, which is for the best book written for young adults each year, and the Odyssey Award, which is for the best audiobook each year.
Basically, YALSA wants to make sure that young adults have a great time at the library, and that they find books and other things that they love.