The book industry has been hit hard by the recession — very hard. (You know publishers are desperate when they start embracing online content curation.) And now there’s even more news to raise the industry’s blood pressure: One in every three people who download e-books on their digital readers do so illegally, according to a survey of 1,959 consumers conducted by a British law firm.

As the Guardian notes, publishers must be quaking in their boots — that’s a ton of lost revenue, plus a quarter of users who admitted to e-book piracy said they would keep on downloading illegally. Record labels notoriously lost millions thanks to Napster (which was eventually ruled illegal), and now publishers are staring down the same tunnel.

Unlike the Napster fall-out, though, no one has attempted a lawsuit yet (and no specific illegal e-book sites had been named in the Guardian article), but there’s little doubt that authors and publishers will be forced to sue if people keep downloading books without paying.

In a way, it’s easier to make the “this is clearly illegal” argument with books – in Napster’s case, the argument was “oh well it’s just 1 song, not an entire album.” But with a book — a large body of work that’s either downloaded in its entirety or not — this justification is much harder. The numbers who admit to illegal downloading indicate that people simply don’t care that they’re essentially stealing books — they aren’t lifting physical objects from stores, so the distinction of taking something illegally isn’t made. (Also an open question: just where are all these people getting their illegal book downloads? Is there a central site that could be shut down?)