At the heart of copyright law is the issue of who is entitled to the proceeds of that copyright, that is, its royalties; if copyright is shared then so too must be the royalties. Anyone credited on the book’s title page is understood to own a share of a book’s copyright and is therefore entitled to a share of the book’s royalties and its library lending fees. Anyone credited on the title page is also included in the book’s cataloguing information.
Anyone credited only on the copyright page is understood not to be a copyright owner of the book, and is therefore not entitled to a share of its royalties or library lending fees but only to the licence fee you paid in order to use the material (such as photographs, quotations, or the book cover design). Those credited only on the copyright page are not included in a book’s cataloguing information. Whether anyone you work with is entitled to a credit on the title page or only on the copyright page is dependent on their contribution to your book and your contract with them.
If a title is jointly authored, then copyright is shared and would be identified as such in the book — “Copyright 2014 by Writer X and Writer Y” — and, in the absence of a contract to the contrary, all contributors would be entitled to an equal share of the royalties. Consequently, if one writer contributes more than the other(s), then the co-writers should enter into a contract that outlines what each party’s contribution is and what portion of the proceeds each is entitled to.
In the case of illustrated works, if the writer and illustrator have collaborated without payment to the other, then copyright is shared as it would be between co-authors and must be identified as such. Again, a contract stipulating the division of royalties is recommended.
If an author hires an illustrator to produce drawings for a book, the copyright to the book remains solely with the author, but the illustrations would either be owned by the author or licensed from the illustrator, depending on the terms of the contract. If the contract states copyright of the illustrations remains with the artist, then the author licenses the images from the illustrator for a set period of time and over a defined geographical area; if the contract states the illustrations are a “work-for-hire,” then copyright of the illustrations is owned by the commissioning author. In either case the contract usually stipulates the illustrator must be credited inside the book and on all marketing materials. Therefore, when negotiating this credit you need to understand that credit on the title page confers greater rights than a credit on the copyright page only.
It may be useful, then, to understand the difference between a book with illustrations and an illustrated book. A book with illustrations is where the text is primary and there are illustrations (or photographs) added throughout the book to increase visual appeal or provide instruction; the illustrations could be removed without losing the content. An illustrated book is where each page is an illustration (or photograph) and the text is overlaid, as in a children’s book or graphic novel; the illustrations and the text are equally essential to telling the story. In a book with illustrations, the illustrator is usually paid a fee to produce the illustrations and may contract to receive credit on the title page or a share of royalties, but this is not a given. In the case of an illustrated book or graphic novel, the illustrator may or may not receive payment up front, he or she receives credit on both the title page and copyright page, and is entitled to a share of royalties and any library lending fees.
Translations are another area where it is common for the individual to be named on the title page: translation is an art in itself, and some translators are as esteemed as the writers they translate. Such a translator will be able to negotiate a credit on the title page and the rights that come with that. Less esteemed translators are often not able to demand a title page credit; instead they will work solely for their fee and a credit on the copyright page. If you hire a translator, again be mindful of what credit you agree to.
If you commission research, editing, illustrations, cover art, and so on for your book, it is recommended that you have a written agreement that specifies it is work-for-hire, that copyright is not conferred upon any other parties, and that any and all claims against the author are limited to payment of the invoice.