One of the top five books we recommend most on the subject, and the only one on that list that actually leans toward a specific suspect (Kosminski). Regardless of your opinions on Kosminski as a suspect, the book provides a wonderful introduction to the case and should be on the shelf of anyone seriously pursuing the investigation. Highly recommended.
Note that in 2004 a new edition of this book was published, titled simply Jack the Ripper: The Facts.