“Adults are only obsolete children.”

“Every once in a while, I get mad. 'The Lorax' came out of my being angry. The ecology books I'd read were dull... In 'The Lorax,' I was out to attack what I think are evil things and let the chips fall where they might.”

“Once-ler! You're making such smogulous smoke - my poor swomee swans, why they can't sing a note! No one can sing who has smog in his throat.”

“You ought to be thankful a hole heaping lot, for The places and people you're lucky you're not!”

“Plant a new Truffula. Treat it with care. Give it clean water. And feed it fresh air.”

“Nor age so eat up my invention.”

“Ideas are the very coinage of your brain.”

“Where art thou, Muse, that thou forget'st so long / To speak of that which gives thee all thy might?”