Content: Properties of tantalum and niobium; Properties of the principal compounds of tantalum and niobium; Applications of tantalum, niobium, and their principal compounds; Economics of tantalum and niobium; Minerals, ores, and concentrates of tantalum and niobium; Metallurgy of tantalum and niobium; Mechanical working and heat treatment of tantalum and niobium. Manufacture of products. Welding; Coatings of tantalum and niobium on base materials; Brief data on characteristic reactions and chemical determination of tantalum and niobium; Two-component alloys of tantalum and niobium; Three- component alloys containing tantalum and niobium; Quaternary and higher alloys containing tantalum and niobium.