The plot of AN INSTANCE OF THE FINGERPOST involves interesting history in an international setting, consistent with the "art history mysteries" of the same author, despite that it occurs some 300 years earlier, soon after the restoration of the British monarchy after Cromwell. The time period involves tumultuous change. The plot mixes Italian merchants, French science, the budding British university system, the search for religious freedom in the American colonies, and the first shy steps of experimental science at the beginning of the Renaissance. The novel's holistic reach into life in England in the late 17th century reaches even to the legal system and the clash of its outdated nature with social attitudes that become increasingly modern.
The very unusual surroundings become familiar to the reader through a triple narration. The events are described by three different persons, each providing a very different perspective. Rather than interweaving the three voices, each description is a separate part of the book. Astonishingly, reading the same story for a second and then a third time is not at all boring. The narrators' backgrounds is sufficiently different to make each story interesting and unexpected.
In such a fascinating setting, a boring novel would be hard to write. The mystery is indeed gripping as it unfolds. The ending, however, disappoints. Rather than a logical solution, the author invokes the mystical. This seems contradictory given that the body of the book appeals to reason.