Photo: Ruben Bolling Trudeau & Doonesbury: A Biography , by Joshua Kendall, was released this week by Abrams Press. It's a thoroughly researched biography of cartoonist Garry Trudeau and his epic, massively influential comic strip "Doonesbury." As revered as "Doonesbury" is, I still think it's underappreciated as a masterpiece of of American art. More than a half-century running, it's a chronicle of the country's late 20th century, early 21st century social, cultural, and political life, read and cherished by hundreds of millions of people, and celebrated and/or feared by the nation's power elite. Because it's a sprawling narrative with a complex web of characters weaving in and out of tales grappling with the time's social/political morality, "Doonesbury" has been called Dickensian in nature and scope. But at an speaking event celebrating the book's publication this week at the 92nd Street Y in NYC, Trudeau suggested an alternative literary analogy. Trudeau, left; Kendall, right.…