This rather compendious volume contains twelve articles, eleven of which have been published in the last twenty years; the last, from which the book takes its title, appears in print for the first time. There are four chapters: "Confirmation, Induction, and Rational Belief" contains the paper "Inductive Inconsistencies" as well as "Studies in the Logic of Confirmation"; "Empiricist Criteria of Cognitive Significance" appears in the section "Conceptions of Cognitive Significance"; the very well-known "The Theoretician's Dilemma" appears in the third chapter—"Structure (...) and Function of Scientific Concepts and Theories"—along with "Typological Methods in the Natural and Social Sciences"; "Scientific Explanation," the fourth chapter, contains "Studies in the Logic of Explanation" and "The Logic of Functional Analysis," as well as the title article. "Aspects" runs to nearly book length and is concerned to survey and contribute to the range of scientific explanation—from physics to history. Hempel discusses the Deductive-Nomological approach and compares it to certain forms of Statistical Explanation; the Covering-law Model of Explanation is introduced and defended against proponents of Explanation-by-Concept, Dispositional Explanation, and Genetic Explanation: Hempel asserts that these three can be subsumed under the Covering-law model. The relation of rationality and decision to Explanation, and the related pragmatic aspects of Explanation are also considered. These are postscripts to certain articles which bring their discussions up to date. There are several rather confusing misprints, but overall the presentation is workmanlike. Hempel's contributions in the philosophy of science have been influential and important, and it is gratifying to have the most important of these collected together.—P. J. M. (shrink)