Are all of his books under the pen name dark and moody?
Yes, mostly
Always sunny
Colorful and cheerful
Random moods
Answer
Yes, most of his books are under the pen name dark and moody. This is because he has been using this pen name for many years and it has become synonymous with his work. He has also written some books under other pen names, but these are not as well-known.
Unravel the Prose: The Fascinating World of Daniel Handler