Worldwide losses in stored products, caused by insects, have been estimated to be between five and ten percent. Heavier losses occurring in the tropics may reach 30% and the net value of losses in storage in the United States has been placed at over $200 million annually. Such loss may reach up to 40%, in countries where modern storage technologies have not been introduced like Ethiopia. These and other factors mentioned in the introductory part of this book are evidences that indicate the relevance of both primary and secondary insect pests as pests of stored products. Therefore, there is a need to understand the basic aspects of storage insect pests (primary and secondary pests) which include: their type, description, life cycle, economic- importance (their status) and the like so as design safe management options to control them. This book, therefore, helps to understand some of the basic aspects of one of the secondary pests (Tribolium castaneum) which include: it description, life cycle, economic- importance (the status) host range and its control options.