Say I have a deep knowledge of an advanced technical topic, and have written a book on such a topic. Though this book does not contain any original research ideas, it is a well written and thorough treatise on a technical topic that is relevant in both academia and industry.
Would writing (and hopefully publishing) such a book help with PhD admissions, or do admissions committees generally only care about research publications (as far as publications go -- obviously they care about recommendations, grades, etc in addition to research)?
If the book were published with a major publisher such as O'Reilly Media, would this make a difference?