Currently reading Alex Fitzgerald’s Myth of Poker Talent. I won’t say it’s the best. It’s also not exactly 100% focused on tournament strategy, but does cover it a good amount. It’s more of his guide book on how not to fail at tournament poker, what you need to study, what you need to put effort in. He’s not a very well-known player; had decent results in the past, though now mostly focusing on coaching. May be little out-dated (2016) but I like his thought process. You may still pick up a few gems from it.