"West of Eden", by Harry Harrison.

"East of Eden", was by John Steinbeck, the author of the "Grapes of Wrath" and (my favorites) "Cannery Row" and "Sweet Thursday". "Doc", the hero of those two novels, and of "Log of the Sea of Cortez", was based on the real-life character Ed Ricketts. Ricketts, a marine biologist pal of Steinbeck, Joseph Campbell, Burroughsand the rest of the Monterey/Salinas/Nepenthe literary circle, always struck me as the archetype of everything that was good and noble and decent in the American soul. His book on the marine biology of the California coast, "Between Pacific Tides", is still in print after over a half-century, and well worth reading by the beachcomber and tidepooler today. He was a man of immense integrity, wit, and knowledge, but a man of action and courage, too. Steinbeck had immense respect for him, as will anyone who gets to learn something about him.

Ricketts, not John Wayne, is what I would consider the quintessential model and example of "a great American", not because he did anything extraordinarily wonderful, but because he lived a worthwhile life.