With this defense of intensional realism as a philosophical foundation for understanding scientific procedures and grounding scientific knowledge, James Fetzer provides a systematic alternative to much of recent work on scientific theory. To Fetzer, the current state of understanding the 'laws' of nature, or the 'law-like' statements of scientific theories, appears to be one of philosophical defeat; and he is determined to overcome that defeat. Based upon his incisive advocacy of the single-case propensity interpretation of probability, Fetzer develops a coherent structure within which the central problems of the philosophy of science find their solutions. Whether the reader accepts the author's contentions may, in the end, depend upon ancient choices in the interpretation of experience and explanation, but there can be little doubt of Fetzer's spirited competence in arguing for