The Buddha’s Enlightenment indicates his acquisition of the supreme knowledge, that is, knowledge of the nature and causes of our existence. This, the Buddha-knowledge, naturally forms the basis of the Buddha’s philosophy and of his solution to the problem of life. Without it, Buddhism cannot be fully understood. But it is strange that no attempt has been made till now to illuminate specifically the Buddha-knowledge; in fact, this subject has been so much neglected that it is not even on anybody’s mind. And we get only limited views of it in the books on Buddhism. A complete, coherent and intelligible description of the Buddha-knowledge is lacking. This slim book, then, is a humble attempt to fill that vacuum.