Sometime in the mid-nineteenth century centrifugal force fell from grace with modern physics. Physics texts from the 1920’s define it, even apply it, yet modern texts ignore or deny it. Newton, Mach, Berkeley and Einstein all used centrifugal force to describe a force that seeks to “flee the center” in a rotating mass. Today, “centrifugal force” appears to have become a bad word in the physics classroom. It is ignored in modern texts, or it is mentioned in denial of its existence. A search of the Internet shows many authorities split on centrifugal force. Some use the term centrifugal force, while others do not. Some say that it was only a misunderstood centripetal force all along. I find it hard to believe the four gentlemen I’ve cited above could have had such a misunderstanding about the subject, yet I’m in no position to argue with the modern authorities who think otherwise. Apparently, there has been a change in thinking and centrifugal force has fallen from grace by many scientists. Can anyone shed light on when this rethinking occurred, and what may have catalyzed it. Do we now look at Newton, Mach, Berkeley, and Einstein as having been incorrect in applying centrifugal force in their work?