Writers are encouraged to write what they know. Composers, too. Take for example Leonard Bernstein’s "West Side Story." Bernstein’s character shows up in a lot of the characters in his megahit musical.

Sid Ramin met Bernstein when they were both 12. They were Roxbury public schoolmates who bonded over music, but also spent time roaming parks and tinkering with mechanical objects — what kids that age do.

Bernstein was a better student than Ramin. He went to Boston Latin and then to Harvard. Ramin remembers the day Bernstein got his acceptance letter from Harvard.

“Nothing deterred him," he said. "I remember standing on a street corner with him. I said, ‘Gee Lenny, you’re going to Harvard.’ And he said, ‘Yes, and I’m going to develop a Harvard accent.’ And he did.”

When Bernstein immersed himself in something, he was all in.

[MUSIC]: When you’re a Jet, you’re a Jet all the way, from your first cigarette to your last dying day ...

Bernstein’s gifts were not only musical. He could hold a crowd just by talking. Sid Ramin, who belonged to a club called The Young Maccabees, invited Bernstein to speak at a club gathering. Ramin recalls that Bernstein got up and made a speech that had everybody so enchanted, the elder people there were saying, this kid of fourteen is speaking like a man of forty.

Even if he had been nervous, Bernstein knew to keep his cool.

[MUSIC]: Boy, boy, crazy boy, stay loose, boy. Breeze it, buzz it, easy does it. Turn off the juice boy … Go man, go, but not like a yo-yo schoolboy … Just play it cool, boy. Real cool …

Harold Shapero and Bernstein were enrolled in a Harvard music class on 16th century counterpoint, a course Bernstein didn’t have much use for. Tillman Merritt was the professor. Shapero recalls that Bernstein never showed up for the class.

“He loved to horse around and stay up all night with his dorm guys,” Shapero said. “Anyway, he didn’t come to class. Around Christmas, it came time for grading. There were no exams, and Lenny had to pass in something. So he came in and played this piece, and Tillman said in his best Harvard accent, ‘You know, Leonard, that’s not exactly what we are doing in the class.’ And Lenny took his fist, banged it on a table, and declared, ‘I like it!’”

Bernstein was unfailingly polite, but comfortable pushing back against authority.

[MUSIC]: Gee Officer Krupke, what are we to do? … Gee, Officer Krupke, [BANG!] Krup You!

Bernstein had a colossal musical talent and outsized confidence. But what propelled him into the hearts of millions was an uncanny ability to connect with people. Shapero recalls a day they were playing catch in his Newton backyard.

They got tired and sat down and started talking. “What’s your ambition?” Bernstein asked. Shapero said his ambition was to catch every girl in the world. Bernstein responded, “That’s not my ambition. I want everybody in the whole world to love me.”

With the release of "West Side Story" as a film, Bernstein’s ambition was realized. But even back then, he must have sensed what was to come.

[MUSIC] Somethin’s comin, I don’t know what it is, but it is, gonna be great …

Judith Kogan is a Boston-based harpist and radio journalist.