I always see people recommend this book, but the reviews on amazon are terrible. I feel like it gets recommended a lot because it's popular/old, not because it's actually good/insightful.
It is insightful and makes us understand the fundamentals of usability - very much like math is for software development. But, it may not be immediately usable for developers in designing web applications. If readers are expecting widgets/screens, they might be disappointed with this book.