Reading this book as a chemical engineer, I probably had an easier time than most, being already familiar with the laws of motion, gravity and thermodynamics.
Even then, it was not a book that could be breezed through easily, despite its short length. This was especially so towards the end of the book as it moved away from classical physics, and in the final two chapters I felt severely out of my depth.
Its difficulty notwithstanding, this is a well written book that summarizes the progress of humankind's understanding of the world through the stories of prominent equations. One can gloss over the technical aspects and still be able to walk away with a good understanding of the journey that was undertaken to get to where we are today. It provides a fresh perspective where progress is not measured in personal terms as we are used to, but in much more meaningful terms as an entire species, with each individual's contribution adding to the entire species' understanding. This alone makes the book worth reading.
Alternatively one can pay attention to the scientific and mathematical aspects of the book, and attempt to follow the train of thought of our eminent scientists, so as to come to their conclusions. This will require a lot of hard work, but the book has made it easier by not omitting the important technical terms and derivation, as well as providing landmark concepts which can be easily Google-d for should one desire more information. At the end of such a reading one will be enriched for having thought through all the concepts himself instead of simply having accepted something handed down to him.
Whichever way the reader decides to explore this book, he will need determination to brave on in the face of unfamiliar symbols and equations, but in the end he will walk away with valuable knowledge.