Chris Matthews reveals his fascination with the elusive spirit of our 35th president in “Jack Kennedy: Elusive Hero” (Simon & Schuster; $27.50). Throughout this incisive book, Matthews presents a balanced evaluation of the leader whose innate qualities were developed and honed by a number of circumstances. As the second son at the same school as his older brother (Joe Jr.), Kennedy showed that he was not a junior edition of his high-achieving sibling by exhibiting his wry humor. But there also were at school the first signs of seriousness, ambition, leadership instincts, political talents and his charisma.

Matthews observes: “There was a lightness to him, a wry Irishness that blended with the WASP manner rather than aspiring to it. With that combination, he could enter where his father, mother, and brother could not.”

Early on, a habit that sprung from his many solitary hospital stays, Kennedy developed a craving for company. Left to himself so often for long periods, he never wanted to be alone as he grew older. New people energized him, bringing out the seductive best in him – his quickness, wit and charm. For his biographer that is a real asset; Matthews is able to use this Kennedy gregariousness to flesh out his exhaustive research through personal interviews.

Early in 1938, President Franklin Roosevelt named Joseph P. Kennedy Sr. ambassador to Great Britain. This turned out to be unfortunate because the senior Kennedy sided with British Prime Minister Neville Chamberlain in “peace in our time” – the move to appease Hitler. Jack Kennedy admired parliamentary backbencher Winston Churchill, who increasingly warned of German military capabilities even as the Chamberlain supporters and Ambassador Kennedy dismissed Churchill as a warmonger.

It is then that a young Kennedy began to break with his father: Should Britain continue to believe that a second world war could be avoided or take a stand to stop Hitler? Here, Matthews shows Jack Kennedy in a masterful exercise in politics: The young American saying that Britain morally should be prepared to fight, and his father saying Britain still should avoid the fight. Matthews observes: “Jack loved courage, hated war. That conflict would define his view of history’s leaders.”

Volunteering for the Navy in 1941, Kennedy found himself posted to the South Pacific, where PT boats’ job was to patrol and to attack Japanese convoys. His courage, determination and leadership magnificently were demonstrated on Aug. 2, 1943. There were 12 men aboard Kennedy’s PT-109 when a Japanese destroyer rammed the boat. In interviews with survivors of the dreadful aftermath – hours adrift in enemy waters with some of the men injured, some nonswimmers – Kennedy kept them together by ordering nine of them to hold on to a plank. Kennedy himself, “Then calmly pulled out his knife, cutting loose a strap of McMahon’s life jacket and taking it between his teeth, he intended to tow him that way,” Matthews writes.

Back from the war, Kennedy the politician began to emerge. Matthews covers the early years in detail, including Kennedy’s aversion to Communism, which had him working with U.S. Rep. Richard Nixon – later to be the 37th president – and even U.S. Sen. Joe McCarthy. According to his aides, Kennedy could be ruthless in politics, as could his brother Bobby. There is a chapter that shows how Kennedy played hardball, even with fellow Democrats.

On the domestic front, Matthews reviews Kennedy’s goals as president. His commitment to the Peace Corps and civil rights, the promotion of science and space travel and the containment of nuclear arms is an exemplary record. On the world stage, Kennedy managed to avert a shooting war with Russia by resisting pressure by the U.S. military leadership to attack Soviet nuclear missile sites in Cuba. Kennedy won a war by averting one.

While lauding Kennedy’s good judgment, Matthews demonstrate his own in the choices of voices he has picked to recount the life of a driven, determined, sometimes frail, always fascinating individual.

Chris Matthews is host of MSNBC’s “Hardball” and NBC’s “The Chris Matthews Show.”