01 Traditional
A publisher takes the book on
Most large publishers accept books only through a literary agent, so you start with query letters or a proposal, then wait. If a publisher signs the book, it pays for editing, design, and distribution, and in return licenses your rights and keeps most of the revenue.
02 Hybrid or assisted
You pay a company to publish
Quality and terms vary enormously. Some are serious publishers; some sell flattery by the package. Read closely who owns the ISBNs, the files, and the rights before you sign.
03 Independent
You become the publisher
You keep the rights and the royalties. You also inherit every stage of the work, to do yourself or to commission from people you have to find, brief, schedule, and check.