As a pioneer and as a passionate advocate of grid systems, Josef Muller-Brockmann (JMB) was undoubtably a master of the grid. This combined with his teaching ability and his exceptionally eloquent and clear writing style has, in my view, given us the definitive work on grids. His may not be the last word but it is the first and arguably the best.
Where his "The Graphic Artist and His Design Problems" (1961) gave us a taste and an outline of grids, "Grid Systems" goes inside grids to examine typography, leading, pagination, formats and more, all in much detail and with an abundance of fine examples. This is an eminently practical book, giving the reader the theory, the method and also examples of grids complete with measurements.
I recommend this book to anyone involved in design. Although it is most applicable to graphic design (print and exhibition), it's application is wider than that, and the lessons will advance the designer's appreciation for the basics and the nuances of good design. Finally, this is an excellent example of writing on design by a systematic thinker, a great designer and an effective teacher. At a time when so much poor writing, ignorance and pretension abounds on the topic of design, this book serves as an exemplary standard for both content, method and style.