“A Promised Land,” the first in a two-volume autobiography by Obama, enters into a tradition as celebrated and popular as it may seem overcrowded and overcrowded. Indeed, according to NPD BookScan, more books on politics have been published and sold since 2016 than in the past 20 years alone. Call it the Trump Bump. Or perhaps a desire to remember the past of the White Houses. But not a week goes by now without a new presidential story, offering revelations, a new perspective, a slice of history so far ignored. Evan Osnos, a New Yorker writer (and former Tribune reporter), even has a slender new bio, “Joe Biden: The Life, the Run, and What Matters Now”. It comes after four years of best-selling books in White House turmoil, many of which are just shiny enough to seem indispensable for a single cycle of cable news. But all have taken their places in a pantheon of Pulitzer winners, quickies and Father’s Day gifts, some ubiquitous (Ron Chernow’s “Alexander Hamilton”), some perpetual (Lyndon’s four-volume epic. Johnson by Robert Caro, awaiting his fifth and final volume someday). Even as I glance at the new presidential books on my shelf, I am struck by the variety: the macro (“First Principles: What America’s Founders Learned From the Greeks and Romans and How That Shaped Our Country by Thomas Ricks ) The mic (Denise Kiernan’s We Gather Together, which deepens Lincoln’s approval of Thanksgiving Day) and the delay (the moving “His Very Best: Jimmy Carter, A Life” by Chicago native Jonathan Alter).