Why Pandemics Happen? is the Second Book of Ashish Kalra, who has also written, "The Killer Bat: COVID-19 Origin and Ramifications". He focuses on 4 Main Drivers for the Pandemic 2020, or 6 lessons for a Post Pandemic World: (a) Disruption of the Animal Food Chain (b) Lessons from the Animal Kingdom (c) Integration of the 'Religion Model' (also using the 'Kalra Mathematical Model for Integration of Religion') (d) Why the World needs to move to a 'Constructive Capitalism' framework as against a "Destructive Capitalism Framework".