A book packager or book producer are terms you'll sometimes see used to describe the person who helps a publishing company put together a book.
Unfortunately, the term can be a bit confusing because various levels of packaging exist. In some cases, a book packager coordinates the writing of the book itself. The publisher gives the packager a marketing concept and the packager finds an author to write or ghostwrite the book. Conversely, sometimes the book packager thinks up an idea for a book, finds writers and other freelancers and then sells the whole thing to a publishing house.
For example, many people are surprised to learn that the popular Nancy Drew, Bobbsey Twins, and Hardy Boys children's series were not written by single authors. Each series was ghostwritten by multiple authors writing under a pseudonym, and produced by the Stratemeyer Syndicate, an early book packager. Various different publishers published the books, but the content, including the writing was completely outsourced to the book packager.
Book packaging is still around too. Some current popular book series, such as selected "for Dummies" books are actually created by book packagers who follow guidelines laid out by the publisher. According to an article in the Los Angeles Times, in 1993 an author named Leslie Whitaker was offered $12,400 to ghostwrite the Beardstown Ladies' Common Sense Investment Guide. Of course, when the book became a bestseller, she was reportedly quite a bit less excited about how the financial negotiation worked out.
Another way to look at a book packager is as a general contractor for books. If you are publishing a book, a lot of coordination of freelancers can be involved. For example, if you are truly self-publishing and have purchased your own block of ISBNs, you might hire a book packager to help you coordinate all the layout, illustration, and printing of your book. You might write the book yourself, but have the packager help you with the rest. If you are busy and working on a complex project, a book packager can save you a lot of time, aggravation, and even money.
In this case, the book packager acts essentially as a book-publishing consultant who either does the freelance work him/herself or hires out tasks such as editorial and design work to other freelancers. (Note that my company Logical Expressions offers this type of book packaging service.)
Unlike a "self-publishing company" (a.k.a. subsidy press), a book packager doesn't have any rights to the book. They don't pay "royalties" or mark up printing. They act as freelancer offering services that relate to the mechanics of producing a book.
If you are self-publishing a book and don't want to (or can't) do all of the work yourself, and you also don't want the drawbacks associated with a subsidy press, working with a book packager is a great option.
LE Book Packaging Services
Not sure you're up dealing with stuff like book layout yourself? I have been laying out books professionally since 1994 and have used almost every desktop publishing program ever made. (These days we use Adobe InDesign.) This page shows you some of the products and services we offer that help people publish their books: