Leishmania donovani is the causative agent of visceral leishmaniasis worldwide. One of the unique features of this unicellular kinetoplastid protozoan parasite is that they have a bisubunit type IB topoisomerase unlike other eukaryotic counterparts and thus it is a potential target for anti-leishmanial therapy. Chapter 1 of this book describes in detail the effect of ATP on the type IB topoisomerase of Leishmania and is aimed for a better understanding of topoisomerase biology in this unicellular protozoan parasite. Leishmaniasis is a dreaded disease of mankind. Chapter 2 of this book...