I had purchased this book as a refresher for print layout (although it could be transferred to digital layout as well). Being educated in design, it’s exactly what you’d expect—in that it reads like a dry text book—which isn’t bad per se. I think there may be a more contemporary book on grid systems. I went with this one because Josef Muller is an OG, and has been around for years, so I knew what I was getting.
This book is a good resource for designers. If I were to teach a typography class this would definitely be part of the required readings. My only issues with this book was that it can be a bit light in content for certain areas of page shaping and grid development. It also works in measurements that you don't see often in the real world, but I think it is good for new designers to have an understand of how these work. Overall it was well worth the money. I keep it on my desk with The Elements of Typographic Style and few history books at all times.
For the novice, this book is an excellent introduction to the purpose and use of grid systems. For the seasoned pro, it offers interesting insights into the small details a grid system can emphasize, or harm, w/any design project.