Definition of copyright
US copyright law limits the right to copy

An adequate definition of copyright requires more than a single sentence.

The idea underlying copyright is that the expression of an idea is property — intellectual property — and its creator has the right control what happens to it. The term copyright literally means the right to copy.

Let's say you wrote a historical novel. You cannot become a rich, famous novelist if you have just a single copy of your work, no matter how great it is. The value of that novel depends entirely on your getting copies of it before the public.

The US Constitution provided legal copyright protection for authors just as it provided patent protection for inventors. The founding fathers thought it unlikely that you (or anyone else) would write or invent for long if you feared that every Tom, Dick, and Harriet could copy your work, sell it, and pocket the profits.

You cannot copyright an idea

The definition of copyright and copyright protection covers only the expression of ideas, not the ideas themselves. In the case of literary and artistic works, the ideas they contain may be very common; what is unique is the way the ideas are expressed.

As a copyright owner, you can make as many copies of your novel as you wish. You can give or sell copies to Tom, Dick, and Harriet without giving up your copyright.

• Tom can give his copy of your novel to the annual library book sale, but he cannot make additional copies of your book.

• Dick can sell his copy of your historical novel on eBay, but he cannot make additional copies of it.

• Harriet can buy the rights to produce a film version of your novel but she cannot make additional copies of your novel.

As the copyright holder, you are the only person with the right to copy the content of your book. Anyone else who wants that historical novel has to get it from you.

How copyright is secured

Under current US law, when someone puts an original work of writing, drawing, photograph, or music into a tangible format such as a piece of paper, computer file, canvas, audio tape, that work is covered by copyright law.

The copyright is the author's legal property from the moment the work is complete. In other words,

• The creator doesn't have to put a copyright symbol © or copyright notice on the work to secure copyright.

• The creator doesn't have to file any forms to secure copyright.

• The creator doesn't have to pay a fee to secure copyright.

You might think of copyright as an invisible tag attached to each work: do not copy under penalty of law.