This is an endeavor to make the graduate students acquainted with the basic knowledge of biotechnology. The book has been written to meet the requirements of B.tech 1st year students (all branches) studying in various engineering colleges affiliated to K.U. Kurukshetra and M.D.U, Rohtak. The book also covers some part of the syllabus of B.Sc. course, and will be of immense help for degree college students. It has been designed to disseminate key information on various aspects of cell biology, genetics, recombinant DNA technology, application of biotechnology in various fields and role of biology in allied fields. The book is divided into 4 units containing 8 chapters in total; each chapter is ended with some selected questions. Unit 1 covers the fundamental concepts on cells structure and functions, their different types and detail study of each cell organelle. The other section of this unit reveals information on various biomolecules viz. proteins, carbohydrates, DNA, RNA etc. Unit II is related to Mendel's laws of inheritance, cell division and its importance, central dogma of the cell and various genetic disorders & their causes. It also includes a chapter on importance of microorganisms in our lives. Unit III and a section of Unit IV is devoted to molecular biology section - a revolutionary science of 21st century. These contain the information on various biological tools and techniques used in biotechnology for creating new gene combinations, and their applications in various fields like agriculture, medicine, environment, forensic science and industry. Another section of Unit IV explains how the study of biotechnology is very much important now-a-days for engineering students as the basics of it should be known to understand the new field like bionanotechnology, bioinformatics and biomems.