IMAGINE that drug companies were so successful at lobbying governments that they won an extension of their patents from 20 years, as they are today, to 100 years; and that the scope of those rights was extended so that future medical discoveries were in effect blocked. The ensuing public outcry would almost certainly result in the law being rewritten in favour of scientific advancement.

Yet this is actually happening (and with little public scrutiny) in a different area of intellectual property: copyright law. As more and more forms of content go digital, the owners of that content are becoming more possessive and turning increasingly to the law for help. The result is a “permission culture”, argues Lawrence Lessig, a professor at Stanford Law School and a leading authority on internet law, where creators increasingly need legal approval for their works, not a “free culture” where creativity is presumptively allowed, as was the case in the past.

Copyright was originally designed to restrict publishers from exerting too much control over information; today it constrains individuals from creating new works. This is because, in America at least, the duration of copyrights has increased (from 28 years in the 19th century to as much as 95 years today), and their scope has widened (to include all works, not just the minority that used to be registered). It now also applies to almost all media, not just printed matter, and to derivative works. Such broad application was never intended, nor existed, in the past.

Although Mr Lessig's analysis sticks to America, the problem he identifies is increasingly a global one. As the internet and computing technology allow more efficient ways to create, share and transform content, large media companies are lobbying for laws and filing law suits to preserve their businesses. Recent suits by the Recording Industry Association of America for millions of dollars lost thanks to music piracy are but one example.

Instead of adapting to the internet, media companies are using the law to change the very features of the internet that make it so successful. Mr Lessig is no cyber-utopian promoting piracy or an end of copyright. Instead, he argues for a more reasonable balance, by redefining copyright law closer to the function that it served in the past. “A society that defends the ideals of free culture must preserve precisely the opportunity for new creativity to threaten the old,” he writes.

The author himself is a partisan. Seeing the deficiencies in copyright law, he co-founded an organisation in 2001 called Creative Commons to allow content-creators to license their works in ways that are open rather than restrictive. (Fittingly, “Free Culture” is available free online for non-commercial use under this system; within days of its release, the book was reproduced in numerous formats, including audio recordings.)

Mr Lessig took his arguments all the way to America's Supreme Court in October 2002. He lost, and the book in many respects is a reply to the majority of the bench who ruled against him. Free culture in Mr Lessig's view is akin to free markets—it does not mean a lack of regulation; it is just a vital platform for progress. Indeed, last year The Economist argued in favour of a return to the 28-year maximum copyright term as a decent starting point for reform. Among the solutions that Mr Lessig proposes—unconvincingly, alas—are copyright marking, registration and renewal, as was done in former times. His final suggestion: “fire lots of lawyers”.

Ultimately, “Free Culture” is about neither law nor technology, the author's areas of expertise. It is about power. Specifically, it concerns the way in which financial and political power are used by corporations to preserve the status quo and to further their own commercial interests. This may be to the detriment of something more socially valuable: a loss of creativity that can never be measured.