By Stephan Lee
October 07, 2014 at 09:56 PM EDT
Seymour Linden

Whether you loved The Giving Tree or found it profoundly disturbing, odds are you still remember the surprisingly complex story by Shel Silverstein of a boy who asks a tree to give him everything. Even on its 50th anniversary today, parents, religious scholars, environmentalists, and feminists are still puzzling and debating over its meaning. Silverstein initially had trouble finding a publisher for The Giving Tree because it was either too sad, too short, or too adult. Fifty years later, it has sold over 10 million copies and was recently released as an e-book — the first of Silverstein’s books to be published in a non-hardcover format.

To celebrate the anniversary, HarperCollins has released a new edition, and the Shel Silverstein estate has shared never-before-seen family photos of the author-artist below:

Shel Silverstein reading, 1959

Silverstein at 18, attending University of Illinois, 1948

Three of Silverstein’s other books, Who Wants a Cheap Rhinoceros?, Don’t Bump the Glump!, and A Giraffe and a Half, are also celebrating their 50th anniversaries this year.