Ropalidia marginata is an common Indian paper wasp which uses paper (wood pulp) to build their nests. There are relatively few records of fungi infecting wasps themselves, a number of fungi having been reported from the nest material. More often, these fungi thrive as saprotrophs and might be associated with the nest material or infect the dead wasps. But to date, information as to the fungi associated with Ropalidia marginata paper nests remains inaccessible. Fungi, being ubiquitous in distribution, are highly successful in survival because of their physiological versatility. Fungi thrive well in most inhospitable habitats with environmental extremes by virtue of their fascinating enzyme machinery. Most fungi produce a plethora of enzymes to break down complex materials for their assimilation and their metabolism. This book therefore provides information about paper nest-inhabiting fungi of Ropalidia marginata and their extracellular lipase activity, identification of promising lipolytic fungal isolates for further industrial applications. This piece of investigation may be useful for researchers belonging to Mycology, Industrial Biotechnology and Biochemistry.