Book excerpt: In Code Warriors, Stephen Budiansky--a longtime expert in cryptology--tells the fascinating story of how NSA came to be, from its roots in World War II through the fall of the Berlin Wall. Along the way, he guides us through the fascinating challenges faced by cryptanalysts, and how they broke some of the most complicated codes of the twentieth century. With access to new documents, Budiansky shows where the agency succeeded and failed during the Cold War, but his account also offers crucial perspective for assessing NSA today in the wake of the Edward Snowden revelations. Budiansky shows how NSA's obsession with recording every bit of data and decoding every signal is far from a new development; throughout its history the depth and breadth of the agency's reach has resulted in both remarkable successes and destructive failures.