This contribution majorly describes the isolation of different collagens from marine Demosponges collected from Gulf of Mannar (GoM), India. Based on the preliminary studies (biochemical and anatomical evaluation of around 40 sponge species collected at GoM), few of the shortlisted sponges were subsequently analyzed for the collagen presence and in particular, Ircinia fusca was focused for further isolation and characterization of different collagens. Chapter I provides background information introducing the subjects presented in the topic of marine sponge biology and its scope. Chapter II...