Shel Silverstein is one of my all-time favourite writers, both for children and for adults. Back in my late adolescence, I played his LP Freaking at the Freakers' Ball to death. The neighbours hated it
Now that I've had grandchildren for over a decade, I've investigated and loved his children's literature.
Now they have worked on a posthumous book of his unpublished works, Everything In It - voluminous by all accounts. You can check it all out here