Speaking as a layperson I found this book gave an extremely wide coverage of recent, & past, philosophy. The varied entries are easy enough for an intelligent layperson to understand, yet they had the depth that would be useful for undergrad philosophy students.
As well as covering the greats, and different branches of philosophy, there was good coverage of contemporary philosophers - something lacking other encyclopaedias/Dictionaries. Also, an eye-opener, was the coverage of some [possibly] curious problems [e.g. death] which, again, are not found in many other works of reference.
In contrast to another recent popular tome [the Cambridge Encyclopaedia of Philosophy] this book is definitely NOT dry and boring. This is important, as it combats the image of the philosopher as a dull academic with nothing of interest to say about life.