Marsten Parker has traded his own account for a living since 1998, following a 14-year career as a software engineer. He initially trained as a concert violinist before switching to computer programming, founding and selling a software company before turning to trading full-time. Parker is the only purely systematic trader featured in Jack Schwager's Unknown Market Wizards — the fifth book in the iconic Market Wizards series — where his long-term track record is documented in detail. A defining characteristic of Marsten's approach is what he calls his "Spirit of Experimentation" — a persistent willingness to question, iterate, and improve. RealTest has evolved alongside his trading practice over more than two decades as his primary strategy research tool, and today serves a growing community of systematic traders worldwide as a purpose-built backtesting and portfolio simulation platform.