Anyone who has ever been the understudy for the lead in a play knows what it's like to be a mere fraction away from the starring role. If the star becomes ill or is unable to fulfill his role, then the understudy must be ready to step into the limelight immediately and shine. If, however, the star is able to carry out his period of commitment, the understudy will find himself twiddling his thumbs and dreaming of what might have been. Such is the position of vice president.

While some vice presidents only ever serve in the capacity to which they were elected, others are eventually called to step up and accept the highest position in the land. Whether they replace a president who can no longer serve or eventually run for office themselves and win, they finally know what it's like to achieve the pinnacle of success.

Kennedy and Johnson, for example, were a pair who never really meshed. Both overtly ambitious, neither man had a sense of closeness or friendship for the other. Kennedy aides and West Wing staffers called Johnson and Lady Bird “Uncle Cornpone and his Little Pork Chop” behind their backs, while Johnson referred to the members of the Kennedy clan and their staff as “Bostons” and “Harvards.” The New England Kennedys and the Texas Johnsons turned out to be another case of the North and the South being unable to come to terms.

"Kate Andersen Brower gives us an in-depth look at each of the most recent vice presidents, their role in history and their relationship with the president they served."

The Gores and the Clintons, however, had what seemed to be a fairy tale relationship with one another for many years. Unfortunately, Bill Clinton's affair with Monica Lewinsky disgusted Tipper Gore to such an extent that their friendly relationship was irrevocably damaged. When Al Gore lost his bid for the presidency in the 2000 election, many blamed the defeat on the scandal and stigma associated with the Clinton years.

Although Biden and Obama started out as opponents both running for the Democratic nomination, they developed a deep and abiding friendship through their years of service together. This relationship extended to their wives as well, allowing the two couples and their children and grandchildren to become like family to one another.

We also find out that Mike Pence, the current vice president, who was a Catholic before he became an evangelical and frequently reaches out to former vice presidents for advice, was chosen partly due to Melania Trump's advice to her husband to choose a running mate without baggage or scandal attached to his name.

In FIRST IN LINE, Kate Andersen Brower gives us an in-depth look at each of the most recent vice presidents, their role in history and their relationship with the president they served. From Richard M. Nixon's service under Dwight D. Eisenhower to Pence's subservience to the current president, we become privy to little-known details of the relationships of the two most powerful leaders in America.

Brower also touches on the lives of the wives of the vice presidents, the so-called second ladies. Just as their husbands each had a relationship with the president they served, so did the second ladies have to contend with (at least to some degree) the first ladies. Like their husbands, some found a comfortable relationship with their somewhat superior counterpart, while others never did.

Additionally, in riveting fashion, we're treated to insider info on the vetting process that each vice presidential candidate undergoes, a tour and history of the Observatory --- the 9,150-square foot, three-story historic home that's part of the U.S. Naval Observatory where the second family lives --- numerous photographs, and endless engrossing details of the circumstances under which some of the vice presidents were suddenly catapulted into the highest position in the United States government, all in an endlessly readable volume.