H. R. Haldeman was President Richard Nixon's White House Chief of Staff from January 20, 1969 to April 30, 1973.
In the Timeless Universe
In the the deleted eighteen and a half minutes of the Watergate tape, Richard Nixon tells H. R. Haldeman about Rittenhouse and the Doc. Nixon tells Haldeman that not only his presidency is at risk if information about Rittenhouse is leaked to the public, but his family as well.
H. R. Haldeman at Wikipedia