Lincoln's books - where to get them?

We've all read Lincoln books, but few of us have ever read Lincoln's books. According to the new head of the National Endowment for the Arts, we're missing some good reading:
This [Barack Obama] is the first president that [who] actually writes his own books since Teddy Roosevelt and arguably the first to write them really well since Lincoln.

Well-written books by Abraham Lincoln: the NEA should make these better known.

p.s. I'm counting up presidential book authors between TR and today and am coming up with Wilson, Hoover, Nixon, Carter, and Reagan (omitting ghost-writing done for Clinton, JFK, and Ike).

If the new head of the Nuclear Regulatory Commission showed not the slightest familiarity with his field, it would matter. If the head of the NEA speaks of Lincoln's books and the last presidential author being TR, that should matter too. History may be parked under the NEH, nevertheless...