After the assassination attempt, Mrs. Reagan turned to Joan Quigley, a San Francisco astrologer, who claimed to have predicted that March 30 would be a “bad day” for the president. Her relationship with Ms. Quigley “began as a crutch,” Mrs. Reagan wrote, “one of several ways I tried to alleviate my anxiety about Ronnie.” Within a year, it was a habit. Mrs. Reagan conversed with Ms. Quigley by telephone and passed on the information she received about favorable and unfavorable days to Mr. Deaver, the presidential assistant, and later to the White House chief of staff, Donald Regan, for use in scheduling.