@LecrystalQC I disagree 100% with the idea that tournaments require a more complex strategy than cash games. Tournaments are often played at stack depths of ~20bb for the majority of them, the majority of decisions are whether to go all in preflop a pretty % of the time in the later stages. I'm not saying tournaments are necessarily easy, but it is generally accepted that cash game strategy is more complex as you are frequently dealing with 100bb+ stack sizes which allow for multiple streets of action.
@fergrberger will have no problem agreeing with that. Harrington is fairly outdated now. It's obviously not totally useless since you can still learn from it about poker fundamentals, but you're better off learning from other sources.