Book excerpt: The American construction industry, reponsible for nearly 4% of the nation's Gross Domestic Product, directly employs over five million people and provides millions of additional support jobs in related fields. This book provides an introductory overview of the economic aspects of the industry, including the historical development of building activity from earliest times to modern day market-based construction, including the work of individual artisans to complex construction unions. The book explores current trends in labor force participation; the measurement of industry performance; the determinants of investment; government involvement; competition; wage determination; training; and worker safety.