I. Introduction. — Historical summary, 236. — Technological summary, 239. — II. 1845–1875. — Early Lake Superior history, 242. — Other districts, 1845–1865, 246. — Discovery of Calumet and Hecla and its development, 248. — III. 1875–1895. — Events of the 1870's in Arizona and Montana, 252. — Butte, Anaconda, 254. — Struggle between the Far West and the Lake, 256. — The Secrétan syndicate, 257. — Technological advances, and their effects, 259. — Depressed prices but growing output in the 1890's, 262. — IV. 1895–1901. — Bingham, Utah, 265. — Anaconda and the Bigelow-Lewisohns, 267. — Michigan developments on the South Range, 270. — The Amalgamated Copper Company, 271. — New discoveries at Bisbee, Arizona, 273. — V. The decade before the War. — Utah Copper and Nevada Consolidated, 276. — Four Southwestern porphyries, 278. — Alaska; Kennecott and Mother Lode, 281. — Arizona; Jerome, Bisbee, and Ajo, 282. — VI. 1914–1925. — Effects of the War, 285. — Low post-war prices and sustained output, 286. — Shifts in production, 287. — The eight leading districts, 289.

I. The Lake; Calumet and Hecla. — Early Organization, 684. — Mergers, 687. — Calumet and Hecla, 688. — II. Butte; Anaconda. — Early mills and smelters, 689. — Consolidation of operations, 692. — The Anaconda, 693. — III. Arizona; Phelps Dodge; Porphyries. Special characteristics, 698. — Phelps Dodge and Bisbee, 699. — Globe, Clifton-Morenci, and Jerome, 703. — IV. American Smelting and Refining Company. — Influence of the Guggenheims, 707. — Tie-up with the Porphyries, 709. — Braden, Kennecott, and Chile, 709. — Present Importance of the Company, 712. — V. Conclusion, 712.