Details techniques for analyzing industries and their component firms, for purposes of making capital-intensive decisions and achieving lasting advantage over industry rivals. Porter postulates five forces driving equilibrated competition: existing rivalries, potential entrants, substitutes, suppliers, and buyers. There are typical positions to take: cost leadership, differentiation, and industry (segment) specialization. Within this framework, the author then identifies ways to analyze market signalizing and competitor movements, dealings with buyers and suppliers, and industry subgroups and evolution. Written in 1980, the book focuses on old-line businesses (e.g., materials or manufacturing), often delving into industry classification by structure or lifecycle (fragmented, emerging, global, etc). The final chapters are more action-oriented, dealing with questions of vertical integration, capacity expansion, and entry into new business. The paradigmatic textbook has recently been challenged on the grounds that no strategy can deliver sustainable advantage.