This document contains lecture notes on big bang disruption from the book Downes and Nunes. It discusses the key characteristics of big bang disruptions, including that they are hard to see coming and stop. Big bang disruptions involve innovations that dramatically disrupt existing industries through better and cheaper offerings enabled by factors like price deflation and marginal cost elimination. The document provides advice on surviving big bang disruptions, such as seeing them coming, slowing the disruption, getting closer to the existing business, and diversifying in a new way. It concludes with thanking the audience and asking for any questions.