In 'Principles of Mining: Valuation, Organization and Administration', Herbert Hoover presents a condensed series of lectures given at Stanford and Columbia Universities. Written for both inexperienced and experienced mining professionals, this book covers a range of topics from the valuation of different types of mines, to the development of mines, to the character and obligations of the mining engineering profession. With a focus on practical applications, Hoover discusses topics such as determining metal content, calculation of ore quantities, and mechanical equipment. He also explores labor efficiency, accounts and technical reports, and the amount of risk involved in mining investments. This comprehensive guide to mining engineering is an invaluable resource for anyone working in or studying the field.