Key Reason to Purchase In 2012 Nassim Nicholas Taleb published the book Antifragile. Nassim defines antifragility as: “Simply, antifragility is defined as a convex response to a stressor or source of harm (for some range of variation), leading to a positive sensitivity to increase in volatility (or variability, stress, dispersion of outcomes, or uncertainty, what is grouped under the designation "disorder cluster").”