William Crapo Durant chartered the General Motors Company in 1908. It acquired four motor vehicle firms — Buick, Cadillac, Oakland (later Pontiac), and Oldsmobile — and several parts manufacturers. Durant's bankers told him that Henry Ford's company was not worth the S8 million in cash that Ford demanded, so Ford did not join.

Harvey Samuel Firestone organized the Firestone Tire and Rubber Company in 1900, joining a group that controlled a "crosswire" patent for solid tires. A large order from the Ford Motor Company in 1906 marked the beginning of a long and important business relationship between the companies and led to a personal friendship between the two owners.

In 1903 the Harley-Davidson motorcycle was introduced by Milwaukee draftsman William Harley, pattern maker Arthur Davidson, mechanic Walter Davidson, and toolmaker William Davidson. Harley-Davidson produced fifty motorcycles in 1906, incorporated in 1907, and by 1917 produced eighteen thousand motorcycles to become the leading U.S...