Have you ever thought about co-authoring a book? Most authors would rather not because they are independent and they don't want people stepping into their creative territory, especially if they are fiction writers.
But no good book is really produced in solitude.
Even if an author does all the writing alone, he or she usually has an editor, as well as people involved in the book's physical production to make its design attractive and to lay it out in a highly readable manner.
Other authors may hire someone to ghostwrite for them, or at least an editor to do substantial editing in organization and content.
In short, collaboration is the key to successful books.
So, why not co-author a book? You might have wonderful ideas for many books you want to write, so many you'll never get them all written, so having someone co-author with you can help you get more done.
It might also help stretch you as an author, making you consider new ideas and writing processes the other author introduces as you work together.
You might also not be much of a writer, so while you have a lot to say, you can depend on your co-author to make your content read smoothly.
What books are most compatible for co-authoring? All of them.
Non-fiction might be a bit easier than fiction, but both can work.
Technology also helps a great deal with co-authoring because authors can be on opposite sides of the country or the globe and still work together.
Manuscripts can easily be sent as Word documents via email, and people can even use programs like Google Docs folders and Gmail to create editable manuscripts.
Turning on the "Track Changes" feature in Word also allows you to edit each other's work and see what the other person changes without your having to fear your co-author will completely rewrite the book and erase your previous work.
If you want to co-author a book with someone, here are some preliminary things to do before the writing begins so you can make sure the project ends up being successful:

1. Find Someone Compatible.
   If you have any question about the likelihood of your getting along with the other person, don't agree to the project.
   
2. Determine Your Mutual Vision.
   A mutual vision is like a mission statement.
   Write up the mission statement for your book.
   You might also write up the back cover copy before you start writing the book.
   The back cover copy is a summary of the book, and in writing it, you will find that you both have to focus on the book's content and purpose.
   
3. Organize the Book.
   Make an outline of the book's chapters and then divide them up between yourselves.
   You may want to alternate writing chapters or writing sections, or just determine, especially with a non-fiction book, to write the sections for the topics in which you are each most knowledgeable.
   With a fiction work, you might first divide up the characters, determining who will be responsible for developing their character traits and keeping track of details so they are consistent throughout the novel; you can still split up the chapters, or you may work closely together brainstorming and writing together as you go along.
   
4. Agree About the Responsibilities and Royalties Beforehand.
   If you co-author a book, you should share the profit.
   That said, if your co-author only writes one-third of the book and that's what you agreed upon, then it's fair that the co-author gets one-third of the royalties, but make sure that the royalties are all agreed upon beforehand.
   It doesn't hurt for the two of you to make up a legal contract in the beginning.
   Similarly, if there are three or more authors, make sure this matter is all clear before you publish the book-the sooner the better.
   
5. Leave Your Ego Behind.
   Read each other's work and make suggestions for changes.
   Reviewing the manuscript requires being honest with each other about the quality of the content, and also being prepared to take criticism from your co-author.
   Remember, the book belongs as much to your co-author as to you.
   Prepare to compromise.
   If there are points upon which the two of you are not able to compromise, agree to let a third party mediate on what should stay in the book or be removed and what needs further development.
   
6. Find a Good Editor.
   Once your chapters are all written and you have both reviewed the book, find a good editor.
   Your editor can be that third party who serves as mediator because he or she is disinterested and will be able to see the book as a whole rather than see it as "What Harry wrote" and "What Sheila wrote.
   " That said, don't give the editor a hard time by arguing and making him act like a referee.
   Accept his judgment, and when you and your co-author are both in doubt, it also helps to find a few other readers to provide feedback.
   Another benefit of your editor is he will be able to ensure the book has one tone throughout so there are no noticeable stylistic differences (unless of course, you want readers to know that individual chapters are by specific authors).
   
7. Determine Marketing Responsibilities.
   Marketing is often the last thing authors think about.
   Once the book is published, you will need to promote it.
   You may be interviewed, need to make public appearances, or do the ground work for mailing out review copies and a host of other things.
   Draw on each other's strengths and admit your weaknesses.
   If you're not good at speaking in public, let your co-author know you don't want to do that part of the marketing, but you are willing to do administrative tasks like researching book reviewers to whom you will mail books.
   
8. Treat Each Other with Respect and Appreciation.
   When you talk about your book in public, don't talk about what you did.
   Talk about the parts your fellow author did that made the book so great.
   Always blow each other's horn.
   It will make you more likeable to your audience and keep your relationship with your co-author strong.
   
9. Let Your Book Have a Life of Its Own.
   You and your co-author are like parents to your book, but just as children grow up, books get published and then have a life of their own.
   Let your book have its own life.
   Let go of it and let it go out into the world to make a difference, whether it's to educate or to entertain people.
   Basically, that means neither you nor your co-author can control everything that happens to your book.
   Keep each other in the loop regarding events or publicity your book gets where you both aren't able to participate, but don't get upset if you disagree about how to promote the book.
   Both of you can do what you think is best and let the book weather whatever publicity it receives.
   

Done properly, co-authoring a book can be a rewarding and enriching experience that can lead to a stronger relationship with your co-author and more collaboration in the future.