Goodnight Opus (ISBN 978-0-316-10853-9) is a 1993 children's book by Berkeley Breathed featuring Opus the Penguin.Goodnight Opus is a take-off of the popular Goodnight Moon children's book; this book actually begins with Opus being read Goodnight Moon by a maternal nanny figure while he sits in bed in his pink pajamas. After the nanny falls asleep while reading, Opus goes on his own journey to say goodnight to all sorts of fanciful beings and animals.