All living beings have their own 'built In' biological clocks which work constantly with precision even when they are kept in constant darkness and at a constant temperature. A natural time sense guides not only the everyday life of the plants, birds and animals but also their seasonal behaviour. This innovative scientific idea has contributed enormously to the understanding of the life sciences in our country. The book explores the scientific concept behind this natural mechanism and presents some fascinating examples in nature. ft 'also gives a simple account of the scientific pursuits in this field and how this knowledge can be used in the service of mankind.