a list compiled by Alex Kasman (College of Charleston)

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Imaginary Numbers (2020)
Seanan McGuire
(click on names to see more mathematical fiction by the same author)

Sarah Zellaby, a running character in McGuire's InCryptid books, is featured prominently in this entry from the series. Sarah's species evolved from insects in another dimension but look essentially like humans. Normally, they are left to be raised as children by human parents, which is why they are called "cuckoos", and by adolescence they kill their adopted families. They then live the rest of their lives using their psychic powers to prey on humans. They are (literally) heartless killers who care only about two things: math and their own survival. At least, that's how it is "supposed" to work. However, Sarah is a "cuckoo" who loves math but also loves the second (mostly) human family that adopted her, joining them as they use their own "super powers" to protect humanity from supernatural dangers.

In this novel, Sarah is abducted by a group of other "cuckoos" who want her to use her for their own purposes, purposes which would likely result in the end of all life on Earth. (Not only human life would be endangered, but also all of the other sentient species that inhabit the planet in this series, including religiously devout little creature that look like field mice, monkey-like furis, incubi and succubi).

Now, let's talk about math.

The title of this book, the cover (which features cool blue mathematical formulas), and the mathematical expression reprinted on the first page of every chapter (which appears to be an approximation of the number of twin primes less than n for no particular reason) all had me expecting that math would play a very big role in this book. I know, I'm guilty of judging a book by its cover, but that's what it led me to believe.

In the first half of the book math just appears to be a personal interest of Sarah's that essentially functions as a security blanket ("prime numbers are some of the most soothing things in the universe...they're always the same, perfect, calming constants that don't change, don't vary no matter how much everything else gets twisted on itself") and a source of lame metaphors ("things that changed everything around them, like a new variable introduced to a formerly stable equation"). We are told over and over how reliable and safe numbers feel to her. She recites prime numbers to herself in times of stress. If you combine this with the fact that she has trouble reading emotions and body language and that she has to work hard to behave normally in social interactions, this comes together to form a rather standard stereotype of mathematical fiction: the autistic mathematical savant. Of course, she also happens to be a psychic insect from another dimension, which doesn't fit the trope, but aside from that these features are very recognizable. I found all of this very disappointing for several reasons. First, it seemed that my initial expectations about math playing a significant role in this book were not correct. Secondly, I consider reliance on such tired stereotypes to indicate very lazy writing on the part of the author. Finally, I fear that those stereotypes reinforce false beliefs about both mathematics and autism.

In the second half of the book, however, the role of mathematics changes drastically. It stops being grade school arithmetic used to provide comfort and becomes math that is important, but too vague to understand. We know that Sarah has to do something with an equation, an equation that is too big, and that the fate of the world hangs in the balance. It is not clear what sort of equation it is. (We are told that it involves numbers and letters.) It also isn't clear what she is doing with the equation. Sometimes it sounds like she has to "balance" it, other times as if she has to "solve" it...or does she just need to understand it? And, the author cannot really explain what makes this equation so difficult for her:

(quoted from Imaginary Numbers)

I'd seen numbers like this before. Not often. They shifted and twisted when I tried to focus on them directly, flickering like candles in a soft wind, never quite going out, never quite holding still. I'd seen these same numbers when I injured myself in New York, blossoming around the edges of consciousness before I hit the ground and everything went away. They meant something. They resolved to something.

The math in this book is not sophisticated. But then, nothing in this book is. The descriptions of the different species, the moral ambiguity, and the twee romance between Sarah and her incubus (adopted) cousin are all presented at a maturity level I would consider suitable only for the "young adult" genre.

Imaginary Numbers ends suddenly on a cliffhanger which is resolved in the sequel Calculated Risks (2021).

More information about this work can be found at
(Note: This is just one work of mathematical fiction from the list. To see the entire list or to see more works of mathematical fiction, return to the Homepage.)

Works Similar to Imaginary Numbers
According to my `secret formula', the following works of mathematical fiction are similar to this one:
  1. Bonnie's Story: A Blonde's Guide to Mathematics by Janis Hill
  2. Calculated Risks by Seanan McGuire
  3. The Peculiarities by David Liss
  4. Middlegame by Seanan McGuire
  5. The Midnighters (Series) by Scott Westerfield
  6. The Number of Love (The Codebreakers) by Roseanna M. White
  7. Zenn Diagram by Wendy Brant
  8. Arcadia by Iain Pears
  9. The Dark Lord by Patricia Simpson
  10. Och fjättra Lilith i kedjor [And Shackle Lilith in Chains] by Åsa Schwarz
Ratings for Imaginary Numbers:
RatingsHave you seen/read this work of mathematical fiction? Then click here to enter your own votes on its mathematical content and literary quality or send me comments to post on this Webpage.
Mathematical Content:
3/5 (1 votes)
Literary Quality:
2/5 (1 votes)

GenreFantasy, Adventure/Espionage, Romance,
MotifEvil mathematicians, Anti-social Mathematicians, Autism,

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Exciting News: The 1,600th entry was recently added to this database of mathematical fiction! Also, for those of you interested in non-fictional math books let me (shamelessly) plug the recent release of the second edition of my soliton theory textbook.

(Maintained by Alex Kasman, College of Charleston)