Every once in a while it turns out that it's just a really good book. Gilbert Strang's books were like that. He actually revised them between editions. I mea

Every once in a while it turns out that it's just a really good book. Gilbert Strang's books were like that. He actually revised them between editions. I mean some editions are totally reorganized. You could tell he did it because he thought the material could be better presented, not just because he could make more money on a new edition.