Steve Keene is the most prolific artist you’ve probably never heard of. By some estimates he’s given away or sold north of 300,000 of his paintings on plywood, which he produces multiple copies of at a time. If you are a fan of the bands Pavement or the Silver Jews or Dave Matthews Band, you may have studied his album art. His paintings are all over the borough: In bars, coffee shops, homes, sometimes left on sidewalks. Now, at 65, he has a book coming out in June, the first to focus solely on his work. And today he joins us from his home in Greenpoint to discuss that work, the book, his reputation and his agenda … or lack thereof.