Funny you should ask about good political memoirs, as I was thinking about such things the other day. Who was the first president to write his memoirs?

Well, I think it was Martin Van Buren (haven't read it, shame on me), right? Did Tyler?

Followed by James Buchanan (read it and liked it, big surprise -- a contrarian, stick-in-Lincoln's eye account of the US leading up to 1861).

Then U.S. Grant, who wrote about his generalship but not his presidency (on my shelf, haven't read it, although it was widely respected and Mark Twain helped get it published. Still in print too).

Did Cleveland publish his? Don't think so, although he did write a book called "Presidential Problems" after he left office.

TR? Good one, I think so, but I cannot call it to mind.

Coolidge wrote the absolute dullest, information free memoir ever.

Hoover must have much later in life probably in the 50s or 60s.

Truman, yes. Eisenhower, not on the presidency if I recall correctly. Nixon, yes. Ford, yes. Carter, yes. RR, yes. Bush...another good question, not sure. BC, now yes.

Thus presidential memoirs are relatively recent phenomena: pre-1900, I count only 3, 1900-1950, 2, 1950-2000, 5.