Stanley Tretick was was of those old-school photographers — he learned the craft as a Marine Corps photographer in World War II — who found himself at the intersection of time and circumstance.

After the war, United Press International sent him on the road with presidential candidate John F. Kennedy, which gave him entree to the White House after the election, where Tretick shot for Look magazine. His photographic perch in Washington put him squarely into the most significant social movement of 20th century America, the civil rights crusade.

Tretick’s shots of the 1963 March on Washington for Jobs and Freedom, many of which have never been published, were found by friend Kitty Kelley in a Marine locker that he left her after his death. Kelley, a biographer who has written about the rich and famous from Jacqueline Kennedy Onassis to Oprah, has written brief stories behind the people and events of Tretick’s photos of that fateful day in a new book “Let Freedom Ring: Stanley Tretick’s Iconic Images of the March on Washington.”

The collection of black and white and color photos capture moments both intimate, such as the Rev. Eugene Carson Blake of the National Council of Churches and Roy Wilkins of the NAACP comparing hats, and public, such as the Rev. Martin Luther King Jr. and other speakers from that day linking arms and preparing to take the march’s first steps.

Let Freedom Ring: Stanley Tretick’s Iconic Images of the March on Washington.

St. Martin’s Press, 161 pages,$24.99.