Pratchett received the NESFA Skylark Award in 2009 and the World Fantasy Award for Life Achievement in 2010. In 2011 he won Margaret A. Edwards Award from the American Library Association, a lifetime honour for "significant and lasting contribution to young adult literature". The librarians cited nine Discworld novels published from 1983 to 2004 and observed that "Pratchett's tales of Discworld have won over generations of teen readers with intelligence, heart, and undeniable wit. Comic adventures that fondly mock the fantasy genre, the Discworld novels expose the hypocrisies of contemporary society in an intricate, ever-expanding universe. With satisfyingly multilayered plots, Pratchett's humor honors the intelligence of the reader. Teens eagerly lose themselves in a universe with no maps."