In twenty articles, scientists from around the world deal with various aspects of repetitive sequences in chromosomes, telomeric sequences and their maintenance by telomerase, chromatin structure and gene activation, centromeric complexity in holocentric chromosomes, translocation frequencies in X and Y chromosomes and evolution of DNA repair mechanism. Four of the articles deal with cytogenetics of certain groups of animals, viz. lepidoptera, fish and birds. Also contains an article on chromosomal radiosensitivity as an indicator of genetic predisposition to breast cancer. The molecular genetics of various cancers, viz. gastrointestinal, lung, prostate and bladder have also been discussed.