MR PENUMBRA’S 24 HOUR BOOKSTORE by Robin Sloan, Book Review

Mr Penumbra’s 24 Hour Bookstore by Robin Sloan is a gleeful and exhilarating tale of global conspiracy, complex code-breaking, high-tech data visualization, young love, rollicking adventure, and the secret to eternal life — mostly set in a hole-in-the-wall San Francisco bookstore. Read on for my full review.

Mr Penumbra’s 24 Hour Bookstore Synopsis

Mr Penumbra's 24 Hour Bookstore - Robin Sloan

The Great Recession has shuffled Clay Jannon out of his life as a San Francisco Web-design drone — and serendipity, sheer curiosity, and the ability to climb a ladder like a monkey has landed him a new gig working the night shift at Mr. Penumbra’s 24-Hour Bookstore. But after just a few days on the job, Clay begins to realize that this store is even more curious than the name suggests. There are only a few customers, but they come in repeatedly and never seem to actually buy anything, instead “checking out” impossibly obscure volumes from strange corners of the store, all according to some elaborate, long-standing arrangement with the gnomic Mr. Penumbra.

The store must be a front for something larger, Clay concludes, and soon he’s embarked on a complex analysis of the customers’ behavior and roped his friends into helping to figure out just what’s going on. But once they bring their findings to Mr. Penumbra, it turns out the secrets extend far outside the walls of the bookstore.

With irresistible brio and dazzling intelligence, Robin Sloan has crafted a literary adventure story for the twenty-first century, evoking both the fairy-tale charm of Haruki Murakami and the enthusiastic novel-of-ideas wizardry of Neal Stephenson or a young Umberto Eco, but with a unique and feisty sensibility that’s rare to the world of literary fiction.

Mr. Penumbra’s 24 Hour Bookstore is exactly what it sounds like: an establishment you have to enter and will never want to leave, a modern-day cabinet of wonders ready to give a jolt of energy to every curious reader, no matter the time of day.

Genre: Adventure, Romance, Fantasy, Mystery

Disclosure: If you click a link in this post we may earn a small commission to help offset our running costs.


Mr Penumbra’s 24 Hour Bookstore reminds me of a cult movie classic combo – Hackers meets The Goonies – with a helping of Gen Y style thrown in.

The shelves were packed close together, and it felt like I was standing at the border of a forest – not a friendly California forest, either, but an old Transylvanian forest, a forest full of wolves and witches and dagger-wielding bandits all waiting just beyond moonlight’s reach. There were ladders that clung to the shelves and rolled side to side. Usually those seem charming, but here, stretching up into the gloom, they were ominous. They whispered rumours of accidents in the dark. So I stuck to the front half of the store, where bright midday light pressed in and presumably kept the wolves at bay.

Robin Sloan’s prose is certainly competent, and what it lacks in literary merit it makes up for in geeky cleverness. The focal point of this story is a puzzle involving books, and overtly so. What’s not to like book lovers?

Did Sloan perhaps create a product that could not have been more perfectly targeted at his consumer demographic?

But before I fall prey to modern cynicism and say we’ll see this as a case study in a product development and marketing textbook one day, let us talk about the additional value to be found amongst the pages of Mr Penumbra’s 24 Hour Bookstore.

Firstly there are many more subtle ‘life puzzles’ considered throughout the novel, for the old and the young.

There is word play. A simple example is on display in the title… the character Mr Penumbra is somewhat of an enigma, and the meaning of the word ‘penumbra’ is ‘a shadowy, indefinite, or marginal area’.

There is its engaging and very personable narrative style.

And, last but by no means least, its endearing characters and their charming stories of personal growth.

Mr Penumbra's 24 Hour Bookstore Quote

With its references to Google and the like this is a story that will not date well. I think knowing this, rather than hide from it, the author instead revels in that fact.

That is the key to the success of Mr Penumbra’s 24 Hour Bookstore – it embraces the transience of modernity.

The story in effect celebrates how inevitable technological change is but equally how enduring the traits of human endeavour, and on a more base level, greed and its counterpart generosity, are.

Why do these sentiments hold such great appeal for readers?

Whether we admit it or not, it is human nature to yearn for what we know and have grown comfortable with; to secretly wish for someone to hit the pause button on the continual evolution of the society we live in, just for a moment so that we can catch our breath. That is the appeal of Mr Penumbra’s book store to our story’s narrator and protagonist Clay Jannon, and the good-natured retro geek chic of this novel about said store was what appealed to me.

Mr Penumbra’s 24 Hour Bookstore by Robin Sloan is a quick and easy read that I dare you, no make that double dare you, not to enjoy.

BOOK RATING: The Story 4.5 / 5 ; The Writing 4 / 5 – Overall 4.25

Get your copy of Mr Penumbra’s 24 Hour Bookstore from:

Amazon Bookshop US Book Depository Kobo Booktopia AU
OR listen to the audiobook FREE with Audible’s Trial (check eligibility)

About the Author, Robin Sloan

Robin Sloan grew up near Detroit and now splits his time between San Francisco and the internet. He graduated from Michigan State with a degree in economics and, from 2002 to 2012, worked at Poynter, Current TV, and Twitter. Check out his website.