This dissertation is a collection of five self-contained papers (not including this introduction). The first three (Chapters 2, 3, and 4) concern desire-satisfaction theories of welfare, Chapter 5 concerns the nature of sensory pleasure, and Chapter 6 concerns the relationship between desire theories and hedonistic theories of welfare. One advantage of this format is that the reader can begin anywhere he likes (the abstract above contains very brief synopses of each chapter). A disadvantage is that the work repeats itself occasionally.