Summary

Part 2: Chain Reactions opens with a chapter called On the Cliff. President Roosevelt met with Britain's Prime Minister Winston Churchill. The two agreed to pool their country's resources to build an atomic bomb. Because Britain was constantly under attack, the work would be done by scientists from both countries at labs in America. Colonel Leslie Groves was chosen to oversee the project. Groves chose Oppenheimer to be in charge of the scientists who would build the bomb. Opponents said Oppenheimer couldn't be trusted because of previous interest in the Communist Party. Oppenheimer said his interest was a thing of the past. Groves insisted he be cleared for the project.

Army doctors gave Oppenheimer a physical but he failed. He was almost six feet tall and weighed just 128 pounds. He was a chain smoker and had a chronic cough. Groves...