From the concentration camps of Dachau and Kolyma, to the Ukraine famine and the American Dust Bowl, to the Moscow metro, the Empire State Building, and the Paris Exposition, the 1930s are brought back to life. Brendon examines the prominent figures of the time -- Hitler, Stalin, Mao Tse-tung, Haile Selassie, and countless others -- in the context of their age. Through a vivid chronicling of contemporary experience, Brendon also gives us a sense of what it was like to be living then; we see the clothes people wore, the food they ate, the suffering they endured.

The central theme that emerges from the book is that the 1930s were a time of systematic obfuscation. Governments fought to maintain control by manipulating the minds of their citizens through the widespread use of propaganda. Brendon investigates how contemporaries knew what they knew, and how much, and to what extent our own view of the time is fogged by their uncertainty. The Dark Valley illuminates a period when the world was struggling with the aftershocks of one crisis while hurtling towards another, the most dangerousin its history.