J. Scott Applewhite / AP President-elect Bill Clinton reacts as former President Ronald Reagan presents him with a jar of red, white and blue jelly beans at Reagan's office in the Century City section of Los Angeles, Nov. 27, 1992.

Every president passes on some piece of advice to those men who follow. Ike showed JFK how to make a quick getaway by helicopter. LBJ told Richard Nixon where he kept the secret tape recorders. Jerry Ford told Jimmy Carter to get around Washington and meet people. And Nixon told Ronald Reagan who to put in  and keep out  of his Cabinet.

But no advice in the history of the presidents club may have been as simple  or stayed a secret for so long  as that imparted by Ronald Reagan to Bill Clinton.

Reagan taught Clinton how to salute. The Presidents Club: Inside the World's Most Exclusive Fraternity

Clinton was lucky when it came to former presidents: he had five at his disposal  Nixon, Ford, Carter, Reagan and George H. W. Bush  the biggest presidents club since Lincoln was inaugurated in 1861. And every member offered to help Clinton in the weeks before he was sworn in.

But Clinton was not expecting a lesson in precision saluting when his motorcade pulled up to Reagan's post-presidential office in Los Angeles in late November 1992, a few weeks after he had defeated Bush. Clinton was mostly paying a courtesy call on the Great Communicator, who by now was 81 years old to Clinton's 46. The two men had met before, in the early 1980s, when Clinton (and his wife, Hillary) attended a White House dinner that Reagan hosted for all the governors.

This time, they sat in Reagan's office mostly talking about safe subjects: the economy, the need to limit spending, the advantages of a line-item veto. When Clinton asked for advice in general, Reagan recommended the curative powers of Camp David.

But then Reagan noted that he had seen Clinton salute during the campaign and found his military method well, a little wanting. If Clinton was going to employ the gestures used by the military, Reagan urged, Clinton needed to be firmer, stronger, more commanding. How much clout you conveyed in office, Reagan understood better than anyone, owed a good deal to how you were perceived.

But how to do it, exactly? The old Army cavalry officer explained the hand had to come up slowly, like it was covered with honey, and then brought down sharply, definitively, as if it was covered with something far less pleasant. Clinton listened and soon the two men were standing in Reagan's office, practicing their salutes together. Photos: Oval Office Secrets from Truman to Obama

The entire session lasted 70 minutes; Reagan awarded Clinton with a jar of jelly beans when it was over. The jar sat on Clinton's Oval Office desk for the next eight years.

Reagan would within a few years admit to having Alzheimer's. His contact with Clinton after 1993 was limited. But across party, across generations, despite political differences, help will always be given to those who ask for it in the presidents club. The jelly beans on Clintons desk stood for that, at the very least.

Adapted from The Presidents Club: Inside the World's Most Exclusive Fraternity, by Nancy Gibbs and Michael Duffy, published by Simon & Schuster.