If any person is looking for just one book to give them an overview of every major western philosophical notion of the last 2500 years this is it. It does not go into as much detail on some specifics as other great classics such as Russell's not so new version of the same title, or Durant's beautiful Story of Philosophy, but it does cover far more ground than any other work in the sense of understanding the big picture of western philosophy.
In reading this book one will gain the best initial understanding of how a certain philosopher connects to another, or how a certain school of thought leads to the next. This book, it is true, does not go into great detail on any particular philosopher. But that is not what scaping histories are for. If that is what is being sought after, buy individual books on individual philosophers or philosophies.
As far as the authorship goes, it is highly readable. It is not quit as beautiful as Will Durant's prose scholarship (though of course no one's is) but it was about as close as a page-turner comes to non-fiction. I found myself highly fascinated and growing deeper in my understanding of overall philosophy - often going through dozens of pages without even noticing. Each chapter flows logically into the next and makes perfect sense. Kenny certainly mastered the art of high quality scholarship without being pedantic.
Basically, if one is anything less than an expert on western philosophy this book holds value. If one has absolutely no, or at least very little, understanding of philosophy then this book will open a whole new world to their mind. Even if said reader is well educated in philosophy this book will increase one's overall understanding so that they may go on to, through other books, better learn of the great many philosophical specifics. I will both gladly and hastily recommend this book as the first for anyone to gain knowledge in philosophy. Surely this will become the standard survey into western philosophy for the next half-century.