Professor Yobbish is the writer of the in-universe book How to Train Your Dragon.
- "Professor Yobbish (BA, MA Hons, Cantab, etc.) has spent many years in the wild observing dragons in their natural habitat. This book is the culmination of his research and it is the definitive textbook on the subject these fascinating creatures.
Professor Yobbish lives alone in a cave on the Isle of Doom. He is theh author of Looking After Your Killer Whale and Sharks and Other Great Pets. He is currently writing a book about butterflies."
- ―How to Train Your Dragon
Professor Yobbish appears to be a self-made naturalist and author of several books of the natural barbaric world. When Stoick sends a letter to him, complaining about the lack of words in his book How To Train Your Dragon ("Yell at it!"), he publishes a second edition ("Yell at it loudly!").