Intelligence is very important in personal development. An intelligent person has a special status in society. In everyday life we decide whether a student is intelligent or not based on school progress but it may be unscientific, e.g. we call a wise person intelligent; but there is a difference between real intelligence and knowledge of the same person. Although there is a close relationship between knowledge acquisition and intelligence, the measure of knowledge is different. So it is the measure of intelligence. Different scholars from different sects of psychology have tried to define intelligence and have also given their own definitions of intelligence. According to Alfred Binet (1905), "Intelligence is the tendency of thought to take and maintain definite direction, the capacity to make adaptations for the purpose of attaining a desired end and the power of self-criticism." We often see in society that students who are considered as intelligent and successful in school life fail in real life. Many people who fail in school life not only succeed in real life but also do great work of guiding the society and revolutionizing the society. There are many examples of such great social reformers. Social intelligence is more important than higher educational attainment, tangible intelligence and quality to be successful in life and in the society. Therefore, it is important for teachers, students and parents to take this concept seriously. It can be explained by some important definitions.