This book expresses the relationship of Linux to UNIX perfectly, and even manages to summarize UNIX and its importance to both computing and, well, the human brain. I mean, this can be life-changing stuff, if you read it right, because UNIX/Linux has an inherent logic, required to solve huge computational problems effectively, and once you start understanding that - then the way you attack real life problems starts to change significantly. It has very directly affected me and my productivity level, and Mike Gancarz expresses all of that very succinctly in this book.