This book contains a collection of critical reviews on the expression of biologically functional proteins in Leishmania and Trypanosoma, which was written by renowned researchers on this field. Species belonging to these trypanosomatids' genera are etiological agents of leishmaniasis, Chagas' disease and sleeping sickness that are extremely debilitating human infection diseases, which remain a major health problem especially in countries from Latin America, Africa and Middle East. Substantiating the problem, the currently accepted drugs for these diseases are quiet unsatisfying...