What it is not: a book that promises to teach you a trading strategy.
What it is: a sort of memoir where the author weaves together his experiences while trading different markets, anecdotes and financial history.
If you think your costs are negligible relative to your edge, you’re wrong about at least one of them. This rule is saying that magical super-profitable trades don’t really exist in the real world. If a trade appears to have far more edge than other available trades, then that appearance is illusory.
I personally found the the author’s attempt to apply trading analogies to real life a bit tedious. But, @naval has 1.4 million followers, so maybe that works.
Recommendation: Must Read.