When his book The Golden Compass won the 1995 Carnegie Medal (awarded by librarians to the best children's book), he gave a speech wherein he stated:

"There are some themes, some subjects too large for adult fiction; they can only be dealt with adequately in a chidren's book. ... In adult literary fiction, stories are there on sufferance. Other things are felt to be more important: technique, style, literary knowingness... The present-day would-be George Eliots take up their stories as if with a pair of tongs. They're embarassed by them. If they could write novels without stories in them, they would. Sometimes they do."

- as quoted by Laura Miller, The New Yorker, Dec. 26 2005 & Jan. 2 2006 double-issue

If you haven't read his The Golden Compass, you should. It's an incredible journey -- fantasy and science fused together into a true adventure. The books are allegedly for children but Pullman is one of the few children's authors who have as many adults as children reading their books.