In some countries, including the United States, copyright law has a constitutional basis. In fact, there is a provision in the United States Constitution that refers to the right of an inventor or creator to have a property interest in the fruit of his or her creative endeavors for a period of time. The underlying concept is that a person should be able to profit from his or her creative and intellectual efforts. The only way that right can be protected is through a legally recognized protection of those interests.

From that starting point, various copyright laws have been written and established through the years. For a significant stretch of time, a person was granted a copyright interest in a piece of his of her work for a set period of time. With that said, a person could then go back and renew his or her copyright interest for another period of time during that person's life. In theory, a person's estate -- following the death of the original copyright owner -- could also renew the copyright for another term.

In time, there was concern that this open-ended approach to copyright law was restricting different intellectual properties -- books, treatises and the like -- from being more widely accessed. The argument was that copyright law -- as established in the Constitution -- was never intended to provide the initial creator of written work with a never ending right to profit exclusively from that copyrighted material.

As a result, beginning in the late 20th century and carrying forward into the 21st century, there were movements afoot designed to change the manner in which copyright law was written and enforced. In short, there was a need to open copyright law which would impose some new restrictions on the copyright creator to exclusively enjoy the fruits of his or her labors for a seemingly indefinite period of time.
A significant revolution in copyright law, such as in the United States, did not happen. Rather, the copyright laws were amended in an act that has become known as the Mickey Mouse Bill or the Disney Bill. (The legislation was enacted when the copyright on Mickey Mouse related materials was set to expire. The new legislation gave new life to Disney in regard to its exclusive interest in Mickey Mouse.)

In any event, by the 21st century, the copyright law in the United States (and which has been adopted in similar forms in some other countries) grants the creator of a piece of written work an exclusively interest in that intellectual property for his or her lifetime plus seventy-five years. Because the legislation arose somewhat through a process of Solomon dividing the baby, it remains the subject of controversy on many levels.