A volunteer reader who reads your manuscript before publication and gives you honest feedback as a regular reader, not an editor.
A beta reader is someone who reads a complete or near-complete draft of your manuscript and tells you how the story lands from a reader's perspective. They're not professional editors. They're your test audience. They tell you where they got bored, which characters they connected with, what confused them, and whether the ending worked. The name comes from software development, where beta testers try out a product before it launches to find problems the creators missed.
You've read your own manuscript dozens of times. You know what you meant by every scene, every line of dialogue, every plot twist. But your readers don't have the story in their heads the way you do. Beta readers show you the gap between what you intended and what actually comes across on the page. They're often the first people to tell you that the twist you thought was shocking was actually obvious from chapter three, or that the side character you barely thought about is everyone's favorite.
Tolkien read chapters aloud to his literary group, the Inklings (including C.S. Lewis), who served as beta readers and gave feedback that shaped the final work.
Rothfuss has spoken about the extensive feedback he received from beta readers over the years he spent revising, including readers who pushed back on pacing and structure.
Meyer's sister was one of her earliest beta readers, whose enthusiastic response convinced Meyer to pursue publication.
Seek out beta readers who will be honest, ideally people who read heavily in your genre and aren't afraid to give critical feedback. Online writing communities are a good place to find them.
Beta readers are most useful when the story is structurally complete and you've already fixed the problems you can see. Don't waste their time on issues you already know about.
If a reader didn't get it, the text didn't communicate it clearly enough. Listen, take notes, and save the defensiveness for your journal. You don't have to take every suggestion, but you do need to hear them.
Get three to five beta readers. If one person is confused by something, it might be a them problem. If four out of five are confused, it's a you problem. Patterns in feedback are what matter.
Write a one-page beta reader questionnaire for your current project. Include five to eight specific questions beyond 'did you like it?' Focus on things like: Where did you stop reading or lose interest? Which character felt the most real? What did you predict about the ending? Were there any scenes that confused you? Having targeted questions gets you far more useful feedback than an open-ended 'thoughts?'