One time, when I went up to San Francisco with a friend, we were walking down Market Street when we were accosted by a man with a dented hat, a wiry brush, and a bottle of glutinous-looking shoe-polish. We immediately refused his offer to polish our (tennis) shoes for $10 apiece, but when the shoeshine man bet my friend that he could determine exactly where he bought his shoes, my friend paused. 
 "Sure thing. Forget the shoeshine, but I'll bet you a dollar that I can tell you, without fail, the city where you got 'em," said the shoeshine man. I tried to tug my friend's arm, but he had already turned back to face the shoeshine man, trying to hold back a malicious grin. My friend is from Greece. His shoes were from Athens. 
 The shoeshine man knelt down over the shoes. "I'll tell you my secret. I just take a look here, and here,"--he deftly pulled out his bottle of shoeshine and squirted a puddle onto the shoe--"and here,"--he used the brush to smear the gunk over the sneakers--"and now I'm gonna teach you an important lesson: never, and I mean never, stop and talk to a busker, because he will trick you every time, and not everyone has my reasonable rates. Welcome to San Francisco, and next time, don't let the friendly faces fool you. Ten dollars for your shoeshine, please." 
 Chagrined, my friend pulled out his billfold and forked over a ten. As we walked away, me wheezing with laughter, my friend checking to make sure his pockets hadn't been picked, we agreed that the experience alone was worth the ten dollars. 
 I think my friend's sneakers were ruined. 
 Mr. Penumbra's Twenty-Four Hour Bookstore was a bit like that shoeshine man. To start with, the opening is intriguing, and I couldn't help but be beguiled by the narrator's voice. Clay was laid off months ago, and he's beginning to feel a bit desperate. As he says,I'd started watching for "help wanted" signs in windows, which is not something you really do, right? I was taught to be suspicious of those. Legitimate employers use Craigslist. 
 So when Clay sees a "help wanted" sign in the window of a bookstore, he walks inside, and despite the rather peculiar requirements of his new post, he's determined to hold onto this job. And the rules seem quite peculiar indeed. Mr Penumbra's Twenty-Four Hour Bookstore seems to have two types of books: the ordinary used miscellany and another rather odder variety, a mysterious set utterly lacking in ASNs and ISBNs that are tucked away on the high shelves in the back. But despite his burning curiosity, Clay can't take a closer look: on his first day on the job, Mr. Penumbra told him sternly that one of the conditions of his employment was that he was not to read the books on those shelves. Clay is a little afraid to Penumbra about these peculiar restrictions:"When people are over a certain age, you sort of stop asking them why they do things. It feels dangerous. What if [...] he pauses, and scratches his chin, and there's an uncomfortable silence -- and we both realize he can't remember?" 
 The odd books tend to be requested by hurried and harried people who rush in at four in the morning, literally trembling until the book they request is in their hands. It isn't long before Clay is devising schemes to discover the secrets that these shelves might hold. 
 As I said, I was initially captivated by Mr Penumbra. A mysterious bookstore? Cryptic clues? A sprinkling of programming nerdery? How could it fail? And honestly, I'm not sure when the magic started wearing off. Like the shoe-shine man's bet, the trick becomes clear just after it is too late to pull out, but long before the final payoff. I was expecting magical adventures in L-space, but instead, all I got were ramblings about Google and some rather illogical plotlines. The ending depends on a trope so threadbare and well-worn that it will come as a surprise to no one. I guessed the "twist" at 47% and then had to wait for the rest of events to catch up. 
 At one point in the book, Clay gets into a conversation about the failure of imagination, and the ways in which our contexts place bounds on our imaginations. Oddly, I found this to be an apt description of Mr Penumbra itself. The technology, and the author's excitement and wonder over it, already feel outdated to me. Most of the stuff about Google's inner-workings was clearly a fantasy, and while I suppose this should have earned a few creativity points, it only added to my sense of letdown. Given the number of things that Sloan made up or got wrong, why didn't he just make up his own megacompany and let his imagination run riot? After all, several other aspects of the book are very, very closely based on our reality, but are given their own names and thus an excuse for deviation from reality. In fact, one of the best things I got out of the book was the impetus to trawl Wikipedia for the history of various fonts to see on what typeface Sloan was basing his creation, and there's a lot of interesting stories there. 
 All the same, just like the shoeshine, I can't say that I exactly regret the experience. Penumbra is certainly a pleasant read, and I still can't help but enjoy Clay's voice and rueful humour. I especially enjoyed the occasional playful use of alliteration such as, "The polish and poise of a PR professional." I can't help but feel that I'm missing something; almost all of the people I follow seem to have given this book glowing reviews. Maybe my discontent is due to a faint sense of resentment that I was taken in, that I was promised Hogwarts but ended up on a stage filled with cardboard cutouts and flashy lighting effects. Although I might not have picked up the book if I hadn't been dazzled by the allure of the mysterious and potentially magical bookshop, I don't regret the hours I gave to the book. Welcome to San Francisco, and next time, don't let the friendly faces fool you. 
 Excerpted from my review on BookLikes., which may have additional quotes and spoilertagged sections.