Through the years the numbers mounted, and today about 10,000 items of Sendakiana, from original artwork to finished editions, fill the Rosenbach - the museum's best calling card with generations that grew up with his books.

But now that card is being recalled. Sendak never gifted the original artwork for Where the Wild Things Are and thousands of other items to the Rosenbach, and the trustees managing his legacy - he died at 83 in 2012 - have asked that the Sendak Collection be returned to them, ending a bond between artist and institution that many assumed would continue in perpetuity.