"Peru in the Guano Age" is a book written by Alexander James Duffield. This book provides a historical account of Peru during the so-called "Guano Age," a period in the mid-19th century when Peru's economy was heavily dependent on the export of guano, a valuable fertilizer made from seabird excrement found on the country's coastal islands.During this era, guano became a valuable commodity in international trade, and Peru's economy experienced a boom due to guano exports. The book likely discusses the economic, social, and political aspects of this period, as well as the impact of guano mining on the environment and the broader historical context of Peru during the 19th century.The "Guano Age" is a significant and unique chapter in Peruvian history, and Duffield's work likely delves into the various aspects of this historical period.