There are a lot of factors when it comes to writing a book. One of them is a good beta reader.
Beta readers (the term comes from computer programming) are readers. Some call them critters (for "critique") or readers. But all of these people do the same task, mostly: they read somebody's written work before it is submitted out to the world, whether that submission is a fanfiction site or the rounds of literary agents.
Writers often find beta readers in their critique groups, if they're part of one, or a circle of writing friends or out of their normal group of friends, the ones who are literary. Beta readers are critical to writers because they can pick up on things the writer can't. Does the story work? Does the plot make sense? How are the characters? After a long time laboring over a story or a book, it's hard to be subjective about the story. That's why handing it over to a different pair of eyes is helpful.
A writing professor I had in college once reminded me that while writing is a solitary occupation, it also involves a group aspect to it--workshops, critique groups, editorial meetings. I've experienced workshopping and I assume that critique groups can't be that different, except the work is probably more polished.
But here's a question---when is the right time to give the draft over to someone to read? I've had friends read just-finished first drafts, but I realized that at that point, I was still uncertain as to where the story was going to, so betas weren't as helpful as they could have been. So I guess the right time to ask and pester is when you know the direction the story is going in, the characters are clear, but there's still a little work left or a little wiggle room for things to change and you, the writer, aren't quite sure what's for the best of the story. Maybe. Anybody have any ideas on this?
Have you ever beta read for someone? What did you do as a beta? Have you had a beta reader? What kind of things--and at what stage of your process--did you allow someone else to read your work?