Includes bibliographical references (pages 369-375) and index.
1. The Double Category of Framed, Relative 3-Cobordisms -- 2. Tangle-Categories and Presentation of Cobordisms -- 3. Isomorphism between Tangle and Cobordism Categories -- 4. Monoidal categories and monoidal 2-categories -- 5. Coends and construction of Hopf algebras -- 6. Construction of TQFT-Double Functors -- 7. Generalization of a modular functor -- A. From Quantum Field Theory to Axiomatics -- B. Double Categories and Double Functors -- C. Thick tangles.