Other than maybe Clarke, this is the last of the giants.
Bradbury was the last of the greats (usually reported as Asimov, Bradbury, Clarke and Heinlein).
We've still got Fred Pohl, Niven, Pournelle, Harry Harrison and a few others. But the list grows thin. Not many folks are writing hard sci-fi anymore.
The Big Four are gone - Asimov, Bradbury, Clarke, Heinlein. Clarke died in 2008.
High praise for Bradbury from Jerry Pournelle: “Ray affected writing more than he intended to: he made short stories look much easier than they are.”