In the United States, all of the rights belonging to the creator of a work become theirs at the time of the completion of that work in a fixed medium. No registration is required, nor does any signed writing need to be executed in order to preserve those rights. Rather, these rights arise entirely from the operation of the statutory law.
Creators rarely take advantage of these rights by themselves, however. The production and distribution of works on a large scale has historically been capital-intensive, so creators of works have generally relied on others to produce the physical copies of their works and distribute them. The idea of copyright developed in parallel with the development of the printing press in the fifteenth century, and it originally protected the rights of printers to exclusively exploit works that they had commissioned. Legal enforcement, and, in particular, international legal enforcement, being what it was in the fifteenth and sixteenth centuries, copyrights were frequently disregarded. Of course, given the systematic violation of copyrights in many parts of the world today, it can be argued that the situation has not changed that much.
The relationship between the creator of a work and its publisher is often an uneasy one. The creator, naturally, wishes to retain both control over the use of the work and the income stream derived from commercial exploitation of the work. The publisher, whether a book company, a record label, or a film studio to take three common examples similarly wishes to retain exactly those same things: control over and income from the work. Because publishing (in whatever format) is a capital-intensive business, the dynamic tends to strongly favor the publisher over the creator of the work, except in the exceptional case of creators who have both a proven track record of generating income from their work and, perhaps more importantly, the ability to negotiate without restriction. The case of musicians and their battles with record labels is particularly well-known.
The most typical trade made between creators and publishers is the licensing of the work in exchange for payments, known as royalties. In the case of books, authors are generally entitled to royalties on every copy sold by the publisher. Music royalties are more complicated because there are more venues in which music can be sold or publicly performed, but the principle is the same. Royalties are generally owed to the songwriter for every copy of an album sold (mechanical royalties), for play on jukeboxes or on the radio (performance royalties), and for use on television or in films (synchronization royalties).
Software publishing, the subject with which this book is primarily concerned, generally does not involve the payment of royalties to individuals. Because commercial software is made, as a general matter, by large teams of people and requires the substantial expenditure of capital, the resulting work is "work for hire." As already discussed, the copyright of such works belongs to the employer, which, in the case of software, is usually also the publisher and the distributor of the software itself.
In general, under the American copyright system an effective monopoly is vested in the creator of each work, subject to relatively few limitations. However, for a number of reasons, most of them having to do with the substantial costs of developing and distributing work in a mass-market medium, rights held under copyright are rarely enforced by the work's creator and very little, if any, of the benefit of the copyright goes to that person. Rather, because of the negotiation of contracts by publishers with the creator or through the doctrine of work for hire, the benefits of copyright flow to the corporations that distribute the work, not the people who create it.