Having read Chantal van der Leest's second book on perfectionism before diving into her first, "Ons onfeilbare denken op het werk," I can truly appreciate her growth as a writer. This debut book serves as a solid introduction to recent research on human reasoning and cognitive errors. However, it lacks the personal touch that makes her second book so relatable and engaging. Despite this, I still found the book informative and enjoyable, learning several new insights along the way.