I often hear from text and academic authors who want to write a nonfiction work that capitalizes on their expertise and writing experience but is aimed at a more general audience. In publishing parlance, that kind of book is a "trade" book, meaning it is sold to the trade -- the booksellers. Usually an author has a yen to communicate with more people, maybe in a different way, and sometimes even on a subject that's not strictly part of his or her professional work or is a passionate but more casual interest. It's admirable to want to take on this new venue, but most academic authors are not well prepared for the differences between the academic and trade publishing worlds. Though these worlds share some traits -- the belief in the need for a well-defined market and a good idea -- they are truly separate. This article is designed to give just a few practical tips for authors who want to leap the divide and succeed.

Why Would Someone Pay Money for This Book? Trade editors generally know that they're competing with every other form of entertainment for readers' attention and disposable income. Unlike academic or professional books, which are contributions to knowledge and thus important to others with the same interests or problems, or textbooks, which are required or recommended for specific courses and thus bought by a very specific audience, trade books are designed to entertain and inform a very broad spectrum of readers. These readers have more than enough interests to support the tens of thousands of trade books published every year, on everything from alternative spirituality to home repair to cooking to politics to movie trivia. All those books share one important characteristic: They have strong commercial potential. People will buy (not just be intrigued by or consider but pay money for) at least 10,000 copies -- theminimum most publishers hope to reach with all their titles.

Any trade editor who looks at a proposal or manuscript will want to know what makes it unique, compelling, and a must-buy for a particular set of readers. The trade market is more uncertain and in its own way riskier than academic and textbook markets. Trade editors make all their decisions in collaboration with their colleagues from marketing and publicity, so they all have to believe that booksellers will support and customers will buy any book they sign up. Since they hear a constant stream of sales pitches from literary agents and authors hawking their books, these editors also tend to be fairly skeptical. The answer to the question of why readers would buy this book must be direct and clear: for example, because they need the information to remodel their houses, gain spiritual enlightenment, have an interest in military history, need to improve their business communication skills, are curious about a favorite celebrity, and so on.

Who Will Buy This Book? In publishing terms, it's also important to define the market--that is, the characteristics of the audience -- for any book as clearly as possible. That can include:

• The general subject: Where in a full-service bookstore would this book be shelved? (If that question isn't easily answered, maybe there's no trade market.)
• The publishing context: Have there been a lot of books published on this subject recently? What are the top two or three best-sellers? Who are their authors and what are their credentials? How does this book and author compare to them? What needs does it answer that existing books do not?
• Demographics: What are the general characteristics of the people who will buy this book? Consider age, related interests, book-buying habits, purpose, gender, race or ethnicity, number of people in this group.
• Timeliness: Why is this book going to be of great interest to this readership two years from now?

Who Is Writing This Book? Most authors who have written successfully for text or academic markets have not had to demonstrate their credibility for a long time. Their track record plus their teaching and other publication credentials give publishers a clear indication that any new book is also very likely to be successful. Those prior credentials also are important in trade publications, especially if the author is writing in the same subject. Often, however, authors seem to want to write outside their professional expertise. A math professor, for example, with a string of successful precalculus titles who wants to write about a spiritual or psychological topic could face resistance from publishers unless he or she can prove expertise in this other subject. That's another reason why it's worthwhile to see who has written the books that compete most closely: What are their qualifications? Their national reputations? Their affiliations?

Even staying within your traditional subject expertise does not guarantee ready acceptance among publishers -- unless, of course, you're a Nobel Prize winner or head of the MIT media lab or have similar notoriety. A trade book has to look like, smell like, and taste like a trade book; it can't have the pedagogical trappings or the professional jargon that are common to text and academic titles. For most academic authors, shifting to writing for a trade audience is challenging (as is the reverse for those authors who have written primarily for general audiences). Expectations about the quality of the writing, assumptions about readers, level and style of discourse, humor, purpose, and almost every other aspect are very different and must be taken into account.

What about the Trade Book Proposal? So how do trade editors get convincing answers to their questions about a book's market and author? They look to the book proposal, a document that is a second-cousin to the traditional prospectus that most authors have done for text and academic books. Like the prospectus, the proposal answers questions about the book, the market, the competition, and the author, but it differs in one key respect: It is a marketing document designed to sell the book to the editor. Style is very much as important as content; the proposal must be lively, compelling, intriguing, and very persuasive. It's entirely possible that an editor could get two proposals for books on the same subject by similarly qualified authors, one written in traditional, severe, perhaps a bit staid academic style and the other written with the appropriate marketing angle and in a catchy prose style. The editor is much more likely to give the latter a second look and serious consideration simply because the author has demonstrated that he or she can communicate to a general audience and has a sense of the project's commercial potential. It's unrealistic to assume that a trade editor can look beyond a business-as-usual prospectus and writing to see a trade jewel glimmering beneath the surface. The proposal must make that jewel sparkle and shine.

There's a whole art to writing successful trade book proposals (and constructing the idea and angle for the books they describe). Some literary agents will advise prospective authors on how to master that art; some authors end up hiring writers or editors to help them. I have a set of brief guidelines that ask a series of prompting questions and give basic advice for would-be trade authors; there are also books on the subject. It's well worth the time it takes to understand how to do a compelling proposal because, unless you are Carl Sagan or Stephen Jay Gould, you'll need it to get editors' serious attention.

Do I Need a Literary Agent? Most trade publishers buy 60 to 70 percent of their titles from literary agents, most of whom are located in New York City, although there are plenty of others around the country. When I say "buy," that's exactly what I mean. Few contracts for trade books are concluded without some kind of advance. The hottest commercial titles, as you've no doubt heard, can go for six figures and even up from there. Typical advances, however, range from $5,000 to $50,000, depending on how the publisher sees the market and the book idea.

The reason that literary agents become important in this kind of publishing scene is that they know specific editors and their particular interests. Trade editors have a fair amount of latitude in what they can buy. Their mandates may come from within the publishing house and its strategy, but often they buy what they like, what grabs them with ideas and writing. They may buy books that fit their own interests, as in the former American studies major who as an editor likes to buy books about popular culture, specifically film and music. Agents (who receive a percentage of the author's advances and royalties) have cultivated relationships with editors and know what they prefer and will buy, so they can connect a project with the right editor. Moreover, agents handle all the business details of the author's relationship with the publisher, from negotiating the contract (which can be quite different from text and academic agreements) to handling any disputes or problems that can come up along the way, even after the book is published. The idea is that the editor and author can focus on the book and writing, leaving the sometimes disruptive business wrangling to the editor and agent.

Can an author place a book without an agent? The answer, of course, is that it's possible, since publishers buy 30 to 40 percent of projects directly from authors. Even more significant, if the project is a specialized trade title, it may be best placed with a smaller house that has an established list in the subject. Since that kind of publisher is quite likely to be eagerly looking for new titles in the area and less concerned about reaching the broadest possible market, an agent in that case is much less important. Placing a more commercial trade project without an agent, however, means creating an exceptionally strong proposal, following accepted protocols, figuring out what publishers and editors should see the project, being stoic about rejection, and being realistic about time frames. Unsolicited and unagented manuscripts often end up in so-called "slush piles," which are screened by editorial assistants and may never reach the editor for whom their intended. Response times can be four to 12 weeks. Nevertheless, authors with strong book ideas who have done their homework and who are persistent stand a good chance of getting a trade editor's attention.

Conclusions: The main point I would like to leave with text and academic authors who want to write a trade book is to be realistic about this very different publishing world. Take those substantial differences seriously and educate yourself about them. As in any new endeavor, do your homework, respect your competitors (i.e., already published books on the subject), understand the processes and the players, do an absolutely bang-up proposal, and get an agent if you need one. And one more piece of advice: If you've got an idea you believe in passionately, don't be intimidated and don't let anyone tell you it can't be done.