Many people harbor a secret fantasy of writing the Great American Novel and then finding the Great American Publisher to put it in the hands of an eager public. In reality, it often takes a significant amount of luck, tenacity and talent to get a book published through traditional outlets. The book publishing industry can afford to be very selective when it comes to publishing new titles, and few unsolicited manuscripts from unknown or unestablished authors are even read by anyone in a decision-making position.
The traditional method many beginning writers use to get a book published is to shop a finished manuscript. This involves mailing a synopsis and sample chapters of a proposed book project to a publisher, who may or may not ask to see the entire manuscript. Sometimes a beginning writer may send an entire manuscript blindly to publishing houses known to publish similar work. In the writing business, this may be called an "over-the-transom" submission, since some desperate writers have been known to toss their entire unsolicited manuscripts through the window above an editor or publisher's door.
The reason why most writers fail to get a book published through an unsolicited or blind manuscript submission is volume. Many publishing houses receive literally thousands of unsolicited manuscripts through the mail every year, and experience has convinced most of them that nothing promising ever arrives "over-the-transom." Assuming an employee is available to read through the "slush pile" of manuscripts, the process can be mind-numbing. Occasionally an author finds the right publishing house, usually a smaller company with a much shorter slush pile, and he or she does get a book published through a traditional "diamond in the rough" route.
Another way to get a book published is to find a legitimate literary agent willing to pitch your manuscript to the right editors and publishers. Almost all major publishing houses rely exclusively on the expertise of literary agents to find the most promising titles. In order to get a book published through a major publisher such as Random House, an author would need the services of a literary agent with a good working relationship with the professional publishing industry. Once a literary agent succeeds in pitching an author's manuscript to a publisher, the book may be put on a publishing schedule. This could be a few months to a few years of downtime before publication, but certain authors may be paid an advance in anticipation of future sales.
Getting a book published through traditional publishing houses has become very challenging in recent years, since major publishers won't read unsolicited manuscripts and smaller publishers are either focused on one particular niche genre or have suffered financially. This reality has led to the increased popularity of vanity presses, publishing companies which contract with individual authors to produce professional-level books for a specific price per book. A vanity press isn't always working in the best interests of an author, but it should produce a marketable book for first-time or local authors who have been routinely rejected by publishers.
There is a difference between having a book printed and having a book published, however. There is a certain feeling of artistic satisfaction whenever a new writer manages to get a book published through a recognized publishing company. Buyers are also more likely to invest in a book containing all the earmarks of a professional publication. While vanity presses or other self-publishing services may allow an author to print a manuscript in book form, it may be better for a serious writer with aspirations towards establishing a writing career to find a literary agent or establish himself or herself with smaller publication credits before approaching a major publishing house with a polished and professional manuscript.