Publishing a book used to involve getting a publisher to offer the author a contract to take their work and produce printed physical copies of it and selling it through bookstores and other retailers. The publisher would buy the right to publish the book in return for paying the author an initial sum as well as a portion of the royalties from its sale. An author could also pay to publish the book themselves (called vanity publishing) or use a print-on-demand service to only publish copies as required.
With the advent of the internet there are a number of other ways that authors can publish their books. The simplest way is to do so electronically by creating an e-book which is not actually printed as a physical book but is rather read online in a digital form using a computer or tablet. This method of publishing a book is available to almost anyone since it is so inexpensive to produce – electronic copies are essentially free – with the author charging a fee to those that want to read the book.