I bought this book because I wanted to learn more about the somewhat "mysterious" subject of philosophy.
On the whole, the book is well written, well presented and full of useful, genuinely interesting information. It's bright, colourful, and most (though not all) of the short chapters contain a brief timeline and a short biography of the philosopher, which I found helped peg a particular idea to a certain time period.
Generally the language is clear and concise, though the authors do occasionally slip into philosophy jargon, though this is perhaps only to be expected given the rather complicated nature of some of the things covered in the book. This was a bit off putting for me, since some of the ideas of the philosophers (Kant in particular, I noticed) are touched upon again later, when mentioning what inspired later philosophers, and I found that since I had not fully understood Kant's ideas in the first instance, I could not understand the ideas of those he inspired.
I was a little disappointed in this book, probably because I expected it to be something that it's not. Aside from the introduction, not much space is given to explaining what philosophy actually is, and definitions of terms such as "epistemology", "existentialism" and "transcendental idealism", while touched upon in the text, are not given as much thought as I would have liked.
As another reviewer has mentioned, I think it would have been better if it had been organised thematically, instead of chronologically. Start off with a section all about epistemology, then go on to logic, ethics, political philosophy et cetera.