In this murder mystery/family drama, Hazel Severy leaves the book store she owns in Seattle and returns to Los Angeles for her grandfather's funeral. Well, he isn't really quite her grandfather. Although she shares his last name, she and her brother were actually orphans who were adopted by Isaac's son, Tom. But, after Tom was imprisoned, the young siblings were basically raised by Isaac himself. She receives a mysterious note from Isaac suggesting that he was murdered and urging her not to tell anyone in her family about the quest he sets her on. Along the way, we meet the whole Severy clan, including her uncles, aunts and cousins. The story touches not only on math and murder but also child abuse, vigilantism, migraine headaches, extra-marital affairs, incest, and Los Angeles traffic. And, it is sufficiently well-written to make all of that fit together with a strange sort of internal logic. Moreover, it was certainly a "page turner" that held my interest.

But, as usual, I will focus here on the mathematics.

In an interview with Publisher's Weekly, the author admits that the titular equation is a "MacGuffin". In other words, it could just as easily have been any other sort of treasure that she was seeking. But, since she chose to make it mathematical, discussions of math and mathematical culture pervade the book. As Jacobs says in the interview, she found the mathematical angle to be motivating: "How does a given character's numerical talents—or lack thereof—shape how they move through life? How does this unifying religion of mathematics affect each member of this family? "

Many members of the Severy family seem unreasonably obsessed with the question of who among them is or is not mathematically talented. Isaac's son Philip is a successful physicist working in string theory, and he is ashamed of his own children's lack of academic success. His sister lives like a hermit and is writing a book on probability that she apparently never intends to finish. And one of Hazel's Severy cousins solved one of Hilbert's problems while working at the Max Planck institute but was scooped by "an unassuming Russian who'd been working on it in his mother's basement for years" and so abandoned math.

One of the main themes of the book is the idea that chaos theory could be used to make stunningly accurate predictions about the future. That is a very unlikely premise, but a relatively common one in mathematical fiction. Here it was perhaps a bit harder than usual to suspend disbelief because the formula is only supposed to be predicting one specific sort of violent event.

Aside from that idea, especially considering that Nova Jacobs seems to have no advanced training in mathematics, the math in this book is pretty good. The mathematics mentioned and the culture of mathematics that were presented seemed relatively realistic to me. And, since I have gotten a bit hyper-sensitive to the sort of misleading or completely misguided representations of mathematics and mathematicians that generally appear in works of fiction by authors with no background in math, an assessment of "relatively realistic" from me is more of a compliment than it may initially sound. On the other hand, although the murder mystery in the book wraps up nicely in the end, the mathematical aspect never gets particularly deep or detailed. I've almost already said all there is to say about the math in the book, in fact. (One of the only very mathematical scenes I can recall at the moment is when Philip analyzes an equation presented to him by the head of a shadowy organization that was pursuing his father.)

I cannot help but wonder where she found out about math, string theory, and the culture of academia. In the PW interview, Jacobs attributes the idea of using math as scenery in this novel to her interest in the fact that the way the nerdy world of Caltech and JPL coexists with the glitz of Hollywood in Los Angeles. So, I am guessing that she has some connection to those institutions, though I have not found it mentioned specifically anywhere. And, she also mentions Ian Stewart's "Letters to a Young Mathematician". So, she presumably also read that. But, none of that explains how she came to thank Princeton Fields medalist Ed Witten for his help with the book. It seems that she has some additional connection to the mathematical physics community. I don't know, maybe like Hazel, her adoptive grandfather was a famous mathematician who died mysteriously in a hot tub. If anyone reading this knows, please share the information with me. It probably is not at all important; I am just curious.

In conclusion, The Last Equation of Isaac Severy is a decent read. It is an entertaining thriller/mystery, and has enough math thrown in to satisfy frequent visitors to this website as well. It has an unusual style, which I alternatively found engaging and annoying. And, it touches on some deep topics relating to family relations, abuse, and revenge. But, mathematically, it didn't have anything particularly interesting to say.