(O'R author and former editor 1999-2006 here) If finance is your only motivation for how you spend your time, do not write a book. It's a very long tail busine

(O'R author and former editor 1999-2006 here) If finance is your only motivation for how you spend your time, do not write a book. It's a very long tail business. Good sales, whether you self-publish or have a publisher, come from great marketing -- the right topic and a high-profile author who is very visible and gets the book noticed by many people. The odds of that being you are very small indeed. Why would anyone write a book? To spread the knowledge, to gain some mana for the author, to gain some mana for the product, to support a consulting business. ("Author of ...") All those motivations are more strongly rewarded when you're published by "A Real Publisher" (doesn't have to be O'Reilly). Real publishers have distribution, and have a brand you and the product and the consulting business can benefit from. If you think you have the reputation and the visibility that will sell your book, definitely think about self-publishing. If you're prepared to invest the time in things that aren't coding and aren't writing (managing reviews, hiring a copyeditor, getting figures, having a professional index built, designing or managing a designer of a cover, etc.) then self-publishing might let you have a commercial success of a book. But books are like startups: most die in the dark. Self-publishing or going with a name publisher is just arguing about 10% vs 90% of bugger all.