* Typo: It's possible you've misremembered the author's name. Perhaps it's a similar name like "Ian Tattersall" or "Ivor Tattersall."
* Specific Genre/Topic: You might be thinking of a book within a specific genre or on a particular topic. Could you provide more information about the book you're looking for, such as the genre, subject, or a few details about the content?
* Non-Published Work: It's also possible that "Ivan Tattersall" is an author who has written but not yet published their work.
To help me find the correct author, please provide:
* Any other details you remember about the book or author: Like the title, publication year, or any other clues about the book's content.
* Any specific genre or topic you're interested in.
With more information, I can help you find the author you're looking for.