In the application of the "Original" Bloom's taxonomy since its publication in 1956, several weaknesses and practical limitations have been revealed. Besides, psychological and educational research has witnessed the introduction of several theories and approaches to learning which make students more knowledgeable of and responsible for their own learning, cognition, and thinking. Hence, a group of researchers revised the "Original" taxonomy in order to overcome its weaknesses and to incorporate the recent developments. The purpose of the present article is to present a concise and critical review of both the "Original" and "Revised" taxonomy with reference to their underlying philosophy, rationale, structure and potential pedagogic uses. (Contains 6 tables.)