Part 1 Classical papers: historical perspective; the structure of DNA, Watson and Crick. The fine structure of the gene: Benzer's study of the fine structure of the gene. The nature of the genetic code: general nature of the genetic code for proteins, Crick et al. Decoding the amber and ochre triplets: the nature of nonsense codons; deciphering amber and ochre triplets, Brenner at al. The search for colinearity: on the colinearity of gene structure and protein structure, Yanofsky et al. Conjugation and genetic recombination: nature of gene transfer in bacterial conjugation, Wollman et al. Genetic regulatory mechanisms: genetic regulatory mechanisms in the synthesis of proteins, Jacob et al. In vivo genetic engineering: transposition of the lac genes; prophage lambda at unusual chromosomal locations, Beckwith et al. Structure-function relationships in proteins: studies of Hemoglobin, Perutz et al. Part 2 Updated papers. Mutagenesis: hotspots for deletions and frameshifts; the specicifity of mutagens, Farabaugh et al. Transposable elements: characterization of transposition; use of transposons as mutagenic agents; mechanism of transposition, Hedges et al. Part 3 Questions, answers, problems and scenarios.