An eight-year battle pushes bitterly forward in Manhattan today as Google makes its case: can digitizing millions of books, with no regard to their author's or copyright holder's permission, possibly be covered under copyright law?

That depends, of course, on how you interpret the aims and effects—on both authors and the public—of Google Books, which has offered up free excerpts from more than 20 million books over a span of nearly a decade. But first some background, via Bloomberg Businessweek.

U.S. Circuit Judge Denny Chin will preside over a hearing at which Google seeks to end an eight-year-old lawsuit by theAuthors Guild and individual writers. If Chin eventually finds Google liable for infringement, it could cost the company more than $3 billion in damages and end a project on which it has spent as much as $40 million annually.

Google's argument is fairly simple: that its bulk copying of books constitutes fair use—the doctrine that offers an exception to copyright law provided that use of the media in question passes several tests. Here's a summary from Merriam-Webster:

a legal doctrine that portions of copyrighted materials may be used without permission of the copyright owner provided the use is fair and reasonable, does not substantially impair the value of the materials, and does not curtail the profits reasonably expected by the owner.

If you've been to college in the past decade or so, you might recall professors citing fair use while, say, photocopying assigned chapters and placing them for free on Moodle or the like. Which is sort of like what Google is doing, eh? So does Google Books pass muster?

It's not so simple. Here's why.

Google has to show that its use of books is "transformative."

In clearer terms, fair use of media must "transform" the work in question by creating some new work or meaning—whether in the service of advancing public knowledge or creating a new work of art or scholarship. Simply placing content online in order to turn a churn a profit doesn't quite fit that test.

For Google, this will be an obstacle. As Businessweek reports, the company is pointing to "other federal circuit opinions that providing content for online searches transforms a work by giving it a new purpose and thus makes it a fair use." But the authors are questioning whether that results in any "transformative purpose," as they well should.

Then again, Google's edge is its search function. As TeleRead's Chris Meadows pointed out last month, that does add value—significantly.

Before Google did its renegade scanning, there was no search index that could search inside books the way it can—because nobody had ever donesuch a widespread book digitization project before. (Because they knew the copyright owners would sue them. Funny how that works.) With all that data, you can do some pretty remarkable things that add a lot of value. But you have to make the copies in order to get that data.

That block quote is legal, of course, by way of fair use.

Google has to show that its project isn't purely commercial in nature.

The attorneys for the Authors Guild have argued that Google's mass scanning is little more than a means to "gain a competitive advantage over other search engines and to generate even greater advertising revenues." Google disputes that assertion. But that also looks like a steep climb, given the advertising revenue Google makes next to search results. 

As one lawyer told Businessweek, "It’s a case where the fair-use doctrine is being misused in a sense because it’s really for purely commercial reasons Google is doing this."

But can authors prove that Google Books has actually hurt their sales at all?

Maybe not. And, unsurprisingly, Google has hopped aboard this defense: "Plaintiffs have adduced no evidence that Google Books has displaced the sale of even a single book," the company argues in a brief. Plus, Google claims that most authors actually want their works to be included in the database, presumably for publicity reasons. (Remember the logic of the myriad musical artists who don't mind Spotify's measly royalties as long as they get the publicity?)

Meadows calls this the "Reese’s Peanut Butter Cup effect of the e-book world": each side is claiming that the other is profiting. Authors say Google is churning a profit by copying their intellectual work. Google claims the authors are the ones benefiting from the project.

But then, is it really so hard to prove that Google Books has hurt authors' sales? There's another thing you'll have noticed in college: when you need to get ahold of a book to finish a reading assignment in a crunch—or you don't feel like paying $22.99 at the school bookstore—Google Books can be a savior, letting students cram from the comfort of a dorm room. Sure, you might have to skip over every three or four pages when they're missing from preview view. But that's a small price to pay for convenience—and can do obvious sales damage from a writer's perspective.

Maybe Circuit Judge Denny Chin will wrap up the case soon, potentially costing Google $3 billion in damages. Or maybe it'll be another eight years of legal wrangling.