I. Combat on Two Fronts.- A. Significance of Two Condemnations.- B. Dialectical Materialism faces its Critics.- C. Stalin and De-Stalinisation.- II. Categories of Diamat and Categories of Science.- A. The Need for Cooperation.- B. The Nature of the Cooperation.- C. Critical Remarks.- III. Definition of the Notion of Category.- A. Precursors.- B. Abstraction of the Categories.- C. The ‘Theory of Reflection’ and Empiricism.- IV. The Dialectic of the Categories.- A. Dialectification of the Categories.- 1. The Concrete Concept.- 2. ‘Fluidity’of the Categories.- 3. Correlation of the Categories.- 4. Tables of Categories.- B. Refusal of a Dialectification of the Categories.- 1. Transition from One Category to Another.- 2. Immanent Bonds.- 3. Contradictions in Thought.- C. Identity of Logic, Dialectic and Epistemology?.- D. System and Method in Hegel.- E. Objective Truth: Absolute and Relative.- V. The Category of Matter: Basis of Ontology.- A. Vulgar Materialism and Dialectical Materialism.- B. The Attributes of Matter.- C. The Materialism of Practice and the Materialism of Matter.- VI. Dialectical Contradiction.- A. Matter and Movement: Evolution.- B. Dialectical Contradiction.- 1. Preliminary Clarifications.- 2. Dialectical Contradiction as Correlation, Opposition and Constitutive Relation.- 3. Dialectical Contradiction and Movement.- C. Transition from Quantity to Quality.- 1. The Categories of Quality, Quantity, and Measure.- 2. The Law of the Transition from Quantity to Quality.- 3. The Importance of this Law.- D. The Law of Negation of Negation.- 1. Content of the Law.- 2. Form of the Law.- 3. Critical Remarks: the Objectivity and Universality of the Law.- VII. Causality-Finality.- A. The Category of Causality.- 1. The Definition of Causality.- 2. Causality in Microphysics.- B. The Category of Finality.- 1. The Nature of the Final Cause.- 2. Critical Remarks.- Conclusion.- Index of Names.