More here, from the editors of the magazine he founded.
For me, I am stunned. We conservatives knew he couldn't live forever. But we wished he could. WFB Jr. was a living legend. I corresponded occasionally with him, on the research and writing I have done on the history of conservatism over the years. He was as erudite and helpful and wise and full of knowledge in private, in encouraging younger conservatives like myself and literally millions of others, as he was in public. I can't believe he's gone. Others have said this, but they're right: he literally changed history (for the better). As George Will has said, before there was Ronald Reagan, there was Barry Goldwater; but before there was Goldwater, there was National Review magazine; and before there was NR, there was William F. Buckley Jr. We shall miss him terribly. But we shall carry on, thanks in part to the foundation he laid. RIP, Bill Buckley.