In this Short Story, Freddy Brick interviews Joe Saluzzi, Partner and Co-Founder of Themis Trading, LLC. In the opening discussion of this two-part series, Joe provides a detailed history of market structure by outlining the evolution of exchanges, the decimalization of stock trading and the prevalence of high frequency trading. Has payment-for-order flow distorted the traditional process of routing trades? In Joe’s opinion, the current market structure leaves a lot to be desired in terms of creating a level playing field for all participants.