This book is a series of articles each looking at the Affair of the Poisons from a different perspective. Although they are tied together by a more or less narrative opening article, the material is at times a little repetitive, as each essay was clearly written to be able to stand alone.
While the book is very readable, and the events are fascinating, this is not really a work of popular history. The original target for the essays was clearly other historians, and her intention in writing them was not so much to build up and explain the characters and the events, as to put the events into the correct social and historical context. In these terms, the book is as far as I can tell, perceptive.
There would certainly be room for a more personal, character-based popular history book on this topic, as an event with secret conspiracies, black magic, illicit sex, murder, religious frenzy and more, all uncovered during a 17th-century detective's special investigation, has all the ingredients necessary for a mass market book.