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Root of Unity  (Russell’s Attic, book 3)

By S L Huang 

24 Sep, 2015

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Third in Huang’s Russell’s Attic series, 2015’s Root of Unity sends protagonist Cas Russell on a treasure hunt. Her quest will pit her against a casually murderous criminal gang and it may well threaten her new friends. The prize is nothing less than a proof that will transform mathematics … and mathematics, or at least a specific application of mathematics, happens to be Cas’ superpower. 

Successful or not, Cas’ quest will definitely raise more questions than it answers. 

Although her powers of calculation are definitely superhuman, Cas falls somewhat short of super-heroic, being the sort of self-centered mercenary who would fit in better with the Secret Six than the Justice League. Having in a previous book acquired a handful of friends — ex cop turned detective Arthur Trestling and hacker Checker — Cas has done her best to moderate her behaviour and to become to be less … evil is the wrong word. Casually murderous might be better. Living up to Arthur’s standards means a lot to Cas, even if she won’t admit it to herself, and falling off the No-Killing-Please wagon bothers her a lot [1].

Cas is busily drowning her guilt in booze when Arthur tracks her down with a request for help: Arthur’s old friend Halliday has developed a new, very efficient integer factorization algorithm, one that could be used to quickly break many common encryption schemes. Apparently Halliday wasn’t sufficiently circumspect about her work, because someone broke into her home and stole her notes, leaving a menacing note as a calling card. 

The logical thing to do would be to call in the NSA. But Halliday appeals to Arthur to recover her work. Arthur in turn ropes Cas into the investigation. The first hint they get that they might be out of their depth comes when goons blast Arthur and Cas off the road with a grenade launcher. The identity of the player on the other side is not at all clear, but what is obvious is that the opponent has access to lots of explosives and is eager to use them. 

Heavily armed goons are bad enough, but there is worse in store for Cas. She fears that she is losing her vital spark as a mathematician. The reason for that may be rooted in a mystery that Cas is reluctant to acknowledge or contemplate: the mystery of who or what Cas Russell really is. 


I suspect I would get more out of these books if I were mathematically inclined, which I am not. However, Huang does a good job of explaining the mathematical concepts relevant to the plot. 

It’s a good thing that Cas is the first-person protagonist in an ongoing series, because otherwise her insistence on treating superhuman calculatory abilities as a form of invulnerability would leave her a bloody smear on the sidewalk. As it is, she comes pretty close to pulling a Sunset Boulevard, narrating from beyond the grave, a number of times in this novel. 

There’s an important lesson here for would-be super-villains, which is as cool as the idea of a big red self-destruct button is, such buttons are more trouble than they are worth. This is something the bad hats would know if they watched Phineas and Ferb so we can tell their cable package doesn’t include Disney. Since this TV series plays with (semi-plausible) superpowers in a semi-realistic world, it’s probably not coincidental that a stock supervillain ploy turns out to be counter-productive. 

Speaking of plot elements that remind me of unrelated series, I got a real Matthew Scudder vibe off Cas in this book. Like Scudder, she suffers from guilt-driven self-destructive tendencies and an extreme reluctance to deal with crippling personal issues. These revelations about Cas do go some way towards explaining why her bad decisions take the form that they do. 

Huang has really stepped up her game in this book. The previous books were good enough to keep me reading, but this one makes me actively anxious to get the next book as quickly as possible. Presumably the next book will be following in short order, so as not to torture those of us who are following the series. 

Root of Unity will be available in a variety of places beginning on September 30th.

1: Which is why you get points for Code Versus Killing during character creation.