If you do choose KO, you might want to follow that up with The Color of Blackjack by Daniel Dravot.
"Knock-out Blackjack", definitely TKO by Dravot, and peruse (for days on end) all the outstanding stuff at BJInfo.
"Blackbelt in Blackjack" is good and later you might check out "Blackjack Secrets" by Wong.
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