The book talks about the change in tactics. At the beginning of the war targeting civilian areas was clearly a war crime; by the end of the war we had things like Dresden.
> And because it had led the AAF to organize its raids during the day, when its bombers were easy for German fighter pilots to find and shoot down, casualties in the bomber force during 1942 and 1943 were shockingly high; in one raid alone, the October 14, 1943 attack on the ball-bearing plants at Schweinfurt (see https://en.wikipedia.org/wiki/Second_Raid_on_Schweinfurt), 26% of the attacking bombers were shot down.
Most people don't understand just how high the casuality rates were. The RAF bomber command lost about 55,000 men of 125,000 total.
Indeed. There is actually an old board game that teaches this lesson more effectively than any history book I've ever come across: Avalon Hill's B-17: Queen of the Skies (https://boardgamegeek.com/boardgame/1032/b-17-queen-skies), first published in 1981.
It's a deceptively simple game: you play as the crew of a single B-17, and follow them over Western Europe in 1942-43. The goal is to make it through 25 missions, the number real-life bomber crews were expected to carry out before being rotated back to the States for non-combat duty.
What makes it so effective is that, after a few games, it quickly becomes obvious that keeping the entire crew alive through 25 missions more or less requires a miracle. A really lucky player will be able to keep the bomber itself going to the end, taking occasional casualties and rotating in new faces to fill their seats, with the result that at the end you look over the crew roster and find half the people you started out with are gone. And that's the lucky player! The less fortunate hit one of the many, many catastrophic failure modes that can bring the entire bomber down in flames long before mission 25 is anywhere near in sight.
In real life it was so rare for a crew to make it through 25 missions that when one finally did -- the crew of the Memphis Belle (https://en.wikipedia.org/wiki/Memphis_Belle_%28aircraft%29), who flew their last mission in May 1943 -- they instantly became national celebrities. So the grim odds the game lays out are depressingly accurate.
(Given its age, it's hard to find pristine copies of B-17: Queen of the Skies today, but there are modern remakes like Target for Today (https://boardgamegeek.com/boardgame/160903/target-today) that are more accessible. Or, if you're willing to wait a little while and live with a used copy of the original game, it's not too hard to get one via eBay. I recommend it if you're interested in the subject; it's a fast play, and since it's a solitaire game it doesn't require assembling a group to play.)