What is the author's tone in The Return of Martin Guerre by Natalie Zemon Davis?

The Return of Martin Guerre is a historical work which has the tone of an investigation. The author, based on the facts of the Martin Guerre case from two eyewitness source books and other historical records, does a lot of guessing about the people involved. Many of the points written about the personalities involved in the case are hypothetical, though based on historical records and the typical activities of peasants in the village of Artigat and the surrounding area of Southern France.