Copyright laws have never been more protective, but, thanks to the Internet, they have never been easier to ignore. Illustration by Thomas Burden

Rod Stewart is being sued over the rights to an image of his own head.

In 1981, a professional photographer named Bonnie Schiffman took a picture of the back of Stewart’s head, which was used, eight years later, on the cover of the album “Storyteller.” Now a different picture of Stewart’s head, also from the back, has been used to promote his Las Vegas act and world tour. Schiffman claims that the resemblance between her photograph and the new image is too close—the legal term is “substantial similarity”—and she is suing for copyright infringement. She is asking for two and a half million dollars.

A copyright is, first and foremost, the right to make a copy. The first products to be protected by copyright—the statutory history begins in Britain, in 1710, with the passage of a law known as the Statute of Anne—were books. Once you buy a book, you can legally do almost anything to it. You can sell it to someone else, you can tear the pages out, you can throw it on a bonfire. God knows you can print terrible things about it. But you cannot make copies of it. The right to do that belongs to the author of the book and his or her heirs and assigns.

As with any right, the right to make a copy is a lot less straightforward than it sounds. As the person who wrote this article, I own the right to make copies of it. Since 1976, in the United States, that right has been born with the article, and there are few formalities still required for me to assert it. The belief that you have irrecoverably forfeited your copyright if you have not sent a copy of your book to the Library of Congress, or put a © on it somewhere, is obsolete.

I have granted The New Yorker an exclusive license to the article for a limited period, after which the magazine retains certain privileges (including printing it in a collection of New Yorker writings and keeping it on its Web site). If, a year from now, someone else, without my permission, reprints my article in a book called “The Most Thoughtful and Penetrating Essays of 2014, ” I can complain that my right to make copies is being violated and, if the court agrees with me, legally suppress the book. Theoretically, the court could compel the publisher to pulp all the unsold copies. Although not the author of this piece, you, too, would likely feel that the publisher of “Most Thoughtful Essays” was a bandit, and you would share my sense of righteous indignation.

But suppose that a Web site, awesomestuff.com, ran an item that said something like “This piece on copyright is a great read!” with a hyperlink on the word “piece” to my article’s page on The New Yorker’s Web site. You wouldn’t think this was banditry at all. You would find it unexceptionable.

This is partly because of what might be called the spatial imaginary of the Web. When you click on a link, you have the sensation that you no longer are at a place called awesomestuff.com but have been virtually transported to an entirely different place, called newyorker.com. A visual change is experienced as a physical change. The link is treated as a footnote; it’s as though you were taking another book off the shelf. The Web reinforces this illusion of movement by adopting a real-estate vocabulary, with terms like “site” (on which nothing can be built), “address” (which you can’t G.P.S.), and “domain” (which is a legal concept, not a duchy).

Some courts have questioned the use of links that import content from another Web site without changing the URL, a practice known as “framing.” But it’s hard to see much difference. Either way, when you’re reading a linked page, you may still be “at” awesomestuff.com, as clicking the back button on your browser can instantly confirm. Effectively, awesomestuff.com has stolen content from newyorker.com, just as the compiler of “Most Thoughtful Essays” stole content from me. The folks at awesomestuff.com and their V. C. backers are attracting traffic to their Web site, with its many banner ads for awesome stuff, using material created by other people.

An enormous amount of Web business is conducted in this manner. Most Web users don’t feel indignant about it. On the contrary, most Web users would feel that their rights had been violated if links like this were prohibited. Something that is almost universally condemned when it happens in the medium of print is considered to be just how digital media work. Awesomestuff.com might even argue that no one is harmed by the link—that it is doing me and The New Yorker a favor by increasing our article’s readership at no cost to us. But the publisher of “Most Thoughtful Essays” could say the same thing, and the court would be unmoved.

This almost instinctive distinction between what is proper in the analog realm and what is proper in the digital realm is at the center of a global debate about the state of copyright law. Statutes protecting copyright have never been stricter; at the same time, every minute of every day, millions of people are making or using copies of material—texts, sounds, and images—that they didn’t create. According to an organization called Tru Optik, as many as ten billion files, including movies, television shows, and games, were downloaded in the second quarter of this year. Tru Optik estimates that approximately ninety-four per cent of those downloads were illegal. The law seems to be completely out of whack with the technology.

The point of Peter Baldwin’s fascinating and learned (and also repetitive and disorganized) “The Copyright Wars” (Princeton) is that the dispute between analog-era and digital-era notions of copyright is simply the latest installment of an argument that goes all the way back to the Statute of Anne. The argument is not really about technology, although major technological changes tend to bring it back to life. It’s about the reason for creating a right to make copies in the first place.

In the United States, the reason is stated in the Constitution. Article I gives Congress power “to promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries.” The Copyright Act of 1790 set the length of copyright at fourteen years, renewable for another fourteen, after which the work falls into the public domain.

A right is just the flip side of a prohibition. The thinking behind Article I is that prohibiting people from copying and selling someone else’s original work is a way of encouraging the writing of useful or entertaining books, just as awarding a patent is a way of encouraging the invention of useful or enjoyable things. The prohibition operates as an incentive for the protected party. For a limited period—fourteen or twenty-eight years—authors get to enjoy the profits from sales of their books, and this prospect of reward induces people to write.

But Article I makes it clear that the ultimate beneficiary of books and inventions is the public. Copyrights are granted and patents are issued in order “to promote the Progress of Science and useful Arts.” This is why the Constitution dictates a limit on the right to make copies. After the term of protection expires, a work cannot be copyrighted again. It becomes a public good. It is thrown into the open market, which allows it to be cheaply reproduced, and this speeds the distribution of knowledge. “Intellectual property is a frail gondola that ferries innovation from the private to the public sphere, from the genius to the commons,” as Paul K. Saint-Amour, one of the leading literary scholars of copyright, elegantly describes it.