Sclerotium rolfsii Sacc. is a facultative parasite of tropical and sub-tropical regions of the world. It incites diseases in several crop plants as well as on wild hosts. Loss in crop yield occurs due to infection at seedling stage. The fungus survives as sclerotia that can resist extremely low to high temperatures. This is the reason that this soil- borne pathogen is difficult to control. The sexual stage (athelial stage) is rarely formed in vitro and has not been reported from nature. We have described here several aspects of biology and control of S. rolfsii based mostly on the work done in our laboratory. Work on variability, secondary metabolites of ooze, mycelia, athelial stage formation and control of S. roflsii through induced systemic resistance (ISR) mediated by plant growth promoting rhizobacteria, other biocontrol agents and plant products has been dealt in detail. Detailed experiments on the role of secondary metabolites in ISR was explored especially through phenolic compounds. Several new observations to science on this fungus are presented here. We hope this book will be useful in research on S. rolfsii.