Parasitology, the study of parasites and their relationships to their hosts, is one of the most fascinating areas of the biology. The parasitology has traditionally been limited to parasitic protozoa, platy helminthes and nemathelminthes, as well as those species of organisms that serve as vectors for parasites. But now a day it is approaching taxonomy, classical morphology, ultra topography, bioecology, epidemiology, molecular heterogeneity, phylogeny, biochemistry and in silico genome analysis to resolves it ambiguity in identification to biodiversity, biotechnology, and clinical diagnosis and health consequences. The protozoan and helminth parasites are fascinating organisms and examples of their parasitism are found in a broad range of hosts, including plants, invertebrates and vertebrates. The interaction between a parasite and its host is complex and dynamic. The scarcity of edited book designed for students and research scholars to use during dissertation or pre-doctoral programs of helmimthes Parasitology in northern India impelled me to produce this work in the form book. This book is written with the objective of providing fundamental knowledge concerning the taxonomy and influence of environmental factors on parasitic helminthes living systems. The book is written for those Graduate, Postgraduate and Researchers who need Morph taxonomic, Bio-ecological and Molecular phylogenetic information and assistance beyond that of an introductory text in general Parasiology. Author is very thankful to learned readers and request to send their valuable suggestions for further improvement of the book into possible future edition.

Dr. Sushil Kumar Upadhyay, is working as Assistant Professor in the Department of Biotechnology, Maharishi Markandeshwar (Deemed to be University), Mullana-Ambala, Haryana. Dr. Upadhyay has 12 years of rich teaching-cum-research experience in the field of Parasitology, Taxonomy, Molecular Biology, Animal and Veterinary Science, Environmental Biotechnology, Bio-Ecology, Nanotechnology, Entomology and Microbiology. Dr. Upadhyay is recipient of the degree of Doctor of Philosophy in Science from University of Allahabad (A Central University) famous as "Oxford of East". He received Undergraduate (Life Science) and Postgraduate (Zoology) degree from Dr. Ram Manohar Lohia Avadh University, Faizabad, Uttar Pradesh. Dr. Upadhyay has achieved various appreciation certificates for his outstanding contribution in the field of Parasitology and Molecular Taxonomy. He has honored by various science societies as FISEC, FSESc, FSSc, FSLSc, FISCA, FZSI, FAGEM, FHSI, FIAZ, FMERC, FBPS, FSEZR in past years and currently member or life member of thirty-two societies, various academic bodies, steering committees and selection panels. His research skill, handling of experimental fauna is excellent and published 11 books and 50 International and National research papers in reputed refereed and high impact factor journals. He has attended and actively participated in 61 seminars/conferences at International and National levels. His contribution for employment to youths at grassroots level for livelihood and sustainability by the mission "transfer of science and technology to grassroots level" and vision "Earn as you learn" is also remarkable and can't be ignored.