There's no point in trying to contact the author for interviews, for advice, for whatever. It's not happening. Fuck that. There's no point. Where's the incentive? People sometimes leave their email address or some contact info in some comments somewhere, but think about it: anyone could contact you back, pretending to be the author. And it just signs you up for more spam, because your email address is sitting around on the web.
What you can do is leave questions in the comments section below, and expect to wait a long time for responses. They'll be put up anonymously, so you have no guarantee that they're written by the author. But any responses that anyone leaves pretending to be the author will be eventually deleted.
So go ahead, ask away. Anything you want to ask, you're going to have to ask in full view of the public. As it should be.