This textbook has been designed to meet the needs of B.Sc. First Semester students of Zoology for the University of Lucknow under the recommended National Education Policy 2020. It comprehensively covers theory and practical papers, namely, Diversity and Biology of Non-Chordata. The theory part of this book aptly discusses the identification and classification of non-chordate animals on the basis of their form and structure and describes the general characters of non-chordate animals. Practical part of the book will make the students understand the taxonomic position and body organization of invertebrates. Relevant experiments corresponding to the theoretical topics and examples have been presented systematically to help students achieve sound conceptual understanding and learn experimental procedures.