Synopsis The story of invertebrate gametes--their structure, origin, composition, physiology, and production mechanisms--was told in Volumes I and II; how accessory sex gland secretions facilitate their packaging, storage, survival, and delivery in Volume III; events leading to and following the union of gametes such as insemination, sperm-egg interaction, fertilization, embryonic and post-embryonic development, embryonic nutrition, eclosion, and larval settlement and metamorphosis in Volume IV (Parts A and B). 'Sexual differentiation and behaviour', the fifth volume in the encyclopaedic series, deals with various aspects of sexual biology of invertebrates ranging from Porifera to Chaetognatha--the patterns of sexuality and their evolution; genetic and non-genetic basis of sex determination; sex ratios; endogenous and exogenous influences in sexual differentiation and maturation; puberty, and aspects of sexual behaviour such as its ontogeny, genetics, species-specificity and evolution, mate recognition and selection, receptivity, courtship, copulatory and post-copulatory behaviour, and the mechanisms controlling mating behaviour. This volume serves as an indispensable corollary and companion to the four volumes that have already appeared in the series.