|No no no...beta.|
What I learned was that, before publishing your book, you gave copies of it to either friends or volunteers to read and give you feedback on what they liked or didn't like. It's similar to the practice of film companies using test audiences to see what they think of a film thus far. There are various opinions regarding what point in the publishing process you should use beta readers, but the one I've read that makes the most sense is when you have the book edited and in a format you believe would be publish-worthy. At that point, you send it to your beta readers to see what other people would think about your work.
I'll admit I probably did it in the most awkward manner. I basically just put it out on Twitter that I was looking for beta readers for "Gods on the Mountain", and advertised it like that for a while. Eventually, I got three people volunteering for the job. I sent them PDF copies of the book, and waited to see what would happen.
Overall, the experience was amazing. My beta readers were open and honest, telling me what parts they loved and what parts they hated. I came to really treasure their feedback because there was one part of the book that at least two of them said didn't work at all, and didn't come across as believable. I went and edited that part, and sent them the edits, and they all affirmed that it was much better. They likewise pointed out any grammar or spelling errors, including one embarrassing mistake where I completely left out the verb!
I definitely saw the value in beta readers from this. I felt like my book was being even more refined, and was beginning to come together as a fully functioning novel. I was happy to have people who could point out problems in the storyline, rather than simply throw my book out into the market and get it from reviewers who may not like the book as much as they could. The experience likewise permitted me to grow and learn to take constructive criticism with a thick skull, and take from others what could help my writing, rather than getting defensive or becoming far too attached to the story.
To any indie authors out there, I would definitely suggest looking up beta readers, or finding those who would function as beta readers for you. It is definitely worth it.