Man by nature is a critical thinker. Likewise all men are philosophers and were born philosophers. The book aims at turning the society into new thinkers who can bring fast revolution in all aspects of development. Within the book different theories are traced and various ideas given by different thinkers about the subject are tackled in detail. Critical thinking is understood to be purposeful, self regulatory judgment that results in interpretation, analysis, evaluation, and inferences as well as explanation of the evidential, conceptual, methodological, criteriological or contextual consideration upon which that judgment is based. Therefore it is as such a tool of inquiry. Critical thinking is a liberating force in education and a powerful resource in one's personal and civic life. While not synonymous with good thinking, critical thinking is a pervasive and self rectifying human phenomenon. The ideal critical thinker is habitually inquisitive, well informed, trustful of reason, open minded, flexible, fair minded in evaluation, honest in facing personal biases, prudent in making judgments and willing to reconsider the views of others.