Michael Lewis opens by examining high-frequency trading — a practice exploiting microsecond-level speed advantages in financial markets — revealing how this practice generates profit through speed advantages invisible and inaccessible to ordinary investors.

Why these microsecond advantages matter so significantly:

• High-frequency traders' technological infrastructure allows them to detect and act on market information fractions of a second before other market participants
• This speed advantage, while individually tiny, accumulates into substantial systematic profit across the enormous volume of daily financial market transactions
• Lewis's detailed reporting reveals mechanisms largely invisible to ordinary investors, who have no awareness of these microsecond-level dynamics affecting their own transactions

This opening establishes the book's central revelation, exposing a previously obscure financial market dynamic to broader public understanding through Lewis's characteristic accessible narrative journalism style.