In the great green room, there is a telephone, and a red balloon, but no ashtray. "Goodnight Moon," the children's classic by Margaret Wise Brown, has gone smoke free. In a newly revised edition of the book, which has lulled children to sleep for nearly 60 years, the publisher, HarperCollins, has digitally altered the photograph of Clement Hurd, the illustrator, to remove a cigarette from his hand. HarperCollins said it made the change to avoid the appearance of encouraging smoking and did so with the permission of the illustrator's estate. But Mr. Hurd's son, also a children's book illustrator and...