The main objective of the manual is to introduce the students of higher secondary stage to the fascinating world of plants, animals and microbes and their complex biological phenomena. The manual covers a complete description of the experiments and exercises. The suggested experiments cover almost all the units/topics including those on diversity in living world, plant, animal and human physiology, genetics, biotechnology and human welfare and environment. A standard format has been used to describe each experiment which includes: @ Aim: It gives a brief title of the experiment under investigation.@ Principle: It is a very brief introduction of the experiment under investigation and explains the biological phenomenon involved. It gives a brief but comprehensive idea about the design of the experiment and explains the significance of the phenomenon being studied.@ Material required: Includes the names of plants/animals to be used as ’samples’; the type of apparatus; the type and quantity of glass-wares required; reagents, chemicals and solutions needed, their concentration and other specification, methods of preparation of solutions and reagents.