COMPUTABILITY, AND UNSOLVABLE PROBLEMS: Hilbert and the Origins of Computability Theory. Models of Computability and the Church-Turing Thesis. Language, Proof and Computable Functions. Coding, Self-Reference and Diagonalisation. Enumerability and Computability. The Search for Natural Examples of Incomputable Sets. Comparing Computability. Godel's Incompleteness Theorem. Decidable and Undecidable Theories. INCOMPUTABILITY AND INFORMATION CONTENT: Computing with Oracles. Nondeterminism, Enumerations and Polynomial Bounds. MORE ADVANCED TOPICS: Post's Problem: Immunity and Priority. The Computability of Theories. Forcing and Category. Applications of Determinacy. Computability and Structure.