This is your basic History of Architecture 101 textbook- it provides an explanation of the elements of architecture followed by a broad survey of the development of architecture in consecutive historical periods, or rather, of "Western" architecture. If you are looking forward to exploring architectural forms throughout the world, you will be sorely disappointed. For instance, Islamic architecture is only briefly noted, leaving an obvious hole between Byzantine architecture and Spanish Baroque. The weakest points of the book are the historical. In many chapters, the focus is entirely on the well-known, canonical architectural works. Additionally, entire ancient cultures are homogenized and over-simplified in favor of a narrative of straight-forward historical progression.
The best parts of the book are in the beginning, where Roth gets to break free of this limiting structure and express creatively the elements of architecture. There are some really cool ideas at play here, as he compares and contrasts architecture from various time periods in terms of their structural elements, rhythm, scale, etc. The final chapters are also quite good, as he breaks out of the canonical works and focuses on buildings he really has something to say about. (And boy does he really have an axe to grind against International Modernism.)
For what it is, though, despite its flaws, it's a really solid introduction to European Architectural history, with plenty of excellent photographs and plans.