This thesis reviews Pliny's career and the composition of his last work, the Naturalis Historia. In the first chapter, the hypotheses of Münzer and Syme relating to Pliny's career are examined and an alternative suggested, according to which Pliny's military career may be dated a decade later than is usually envisaged. Chapter two dates the composition of the NH to either 72-78 or 76-78. Chapter three examines Pliny's working time-table and offers comparison with Cicero's time-table in 45 B.C. Chapter four reviews the various resources available to Pliny for research. Chapter five examines his working-methods and suggests a possible format for his commentarii. There are thirteen appendices, seventeen figures, and eight maps.