John Green has been so manically busy promoting the movie adaptation of his novel, "The Fault in Our Stars," that you would never guess he was initially opposed to making it. He was certain at first that a Hollywood version of his story, about two teenagers with cancer who fall in love, would be maudlin.

"I thought there was no way anyone could make a Hollywood version of 'The Fault in Our Stars,' period," he said in an interview. "I didn't want to be in a meeting discussing whether the girl in the...