These excerpts from letters to partners of Buffett Partnership, Ltd. (BPL) summarize the firm's financial performance and investment philosophy during 1964. The mid-year report notes performance generally aligned with the Dow-Jones Industrial Average (DOW) during an advancing market, while the year-end report confirms BPL significantly outperformed the DOW and several large investment companies, although the margin of superiority was the smallest since 1959. Warren Buffett consistently emphasizes the importance of objective performance measurement against the DOW and criticizes the poor results of highly-paid professional management in the broader investment company industry. The year-end letter also introduces a revised four-category framework for BPL's investment operations and discusses the firm's approach to taxes and conservatism, stressing that minimizing taxes is secondary to maximizing after-tax compound rate.