First, I must warn you: this is not a Sherlock Holmes book. It is a science book using Sherlock Holmes charecters. It is also not realistic, in that there are anumber impossible situations (like a century-old atom bomb accidentaly being set off), and many scientific priciples discussed were not discovered until decades after the victorian era (the setting for the book) However, this does not make it a bad book. In fact it is an excelent book. It does a great job of explaining physics principles, even quantum mechanics, enjoyably and in layman's terms. It would probably be enjoyable for both adults who want to get an overall idea of the more unusual physics and for teaching high-school level physics. The earlier chapters can be used with younger students. Overall, a very good book.