In more detail: when an author "sells" their manuscript to the publishing house, they're paid an advance against royalties. Every time a book store sells a copy of the published book to a member of the public, the book store pays the publisher for the book, and the publisher in turn pays the author a percentage of the profits brought in by that sale. This is known as a royalty, and it's not high — for most authors, we're talking single-figure percentage rates. This is because the publisher is taking the risk of paying the author in advance, printing and distributing the book, etc.

At first, because the publisher has paid the author that advance against royalties, 100% of the profits of every sale goes straight back to the publisher. Once enough copies of the books have sold that the advance has been paid back to the publisher — a process known as earning out — the royalty comes to the author (in a bulk payment once every six months), and the rest of the profits go to the publisher.

So, while it is financially better for me in the short term for you to buy your own copy, in that I eke my way one book sale at a time closer to earning out, I understand how expensive books can be, and the competing demands placed on your paypacket each week. And hey, much as I love books, I'm not choosing to buy a book over paying my rent, either.

And the short-term is not the only consideration at play here. In the long-term, what's best for me and my fledgling writing career is that people hear about my book. The best kind of advertising is word of mouth, because people trust their friends' opinions far more than they'll trust sales hype.

So if you borrow a copy of the book rather than reading it yourself, don't guilt-trip yourself over starving an author. Instead, pay the author back in a way that is in your power and doesn't cost you a cent: if you like the book, recommend it to someone you think might also like it.