I must admit, I thought R C Sproul was dead. He's one of those famous names who knowledgeable people namedrop and quote alongside others who definitely are dead. A bit like Johnny Cash, he just seems to have been around forever and for a while had dropped off my radar. But over the last year or two he's enjoying a resurgence (again like Johnny Cash did) and is writing, blogging and pumping out some great stuff. In his latest book, Unseen Realities; Heaven, Hell, Angels and Demons, he revisits some of the territory that CS Lewis explored in The Screwtape Letters. You can get a sample of the book here. His main focus is Ligionier Ministries (superb website here) and with regular audio and video postings here. A biography of Sproul is available here.