Originally, I started reading this to force myself to deal with anthropology - it was part of my Human Biology class and I needed to know about it for the exam. However, I didn't like the topic during the lecture - all those monkeys and humanoids were simply boring.
However, when I started reading this book, I could actually feel a lot of Johanson's excitement for his discoveries. The first few chapters are the most interesting ones and the exam is long written (and passed - partly thanks to this book, or the bit of enthusiasm for anthropology it awakened in me), but I decided to finish the book anyway. Can't hurt to learn more, can it?
One of my favourite parts after the exciting tales about finding Lucy and other Australopithecines was the explanation of how K-Ar dating works. It was comprehensible yet detailed enough to satisfy my curiosity (mostly, I still read the Wikipedia article).
While I can't say I loved the book, it was definitely a very interesting read.