The 18 verses of Isha Upanishad, which also appear in the Veda, were most dear to Sri Aurobindo in the sense that he has attempted several commentaries upon them in order to break free from the anomalies occuring in the received interpretations. In the process, he has audaciously ventured to disagree with many venerated masters and philosophical doctrines. Now that all these commentaries are available in one single volume, one should relish the delightful arguments and illumining explanations. It is important to know that, out of the repeated revision of these commentaries was born, 'The Life Divine', by far, the greatest philosophical work to date. His shorter commentary on the Kena Upanishad deals with epistemological issues while that on Isha takes up the ontological aspects. These works are much more accessible than the sophisticated idiom of 'The Life Divine', and, in fact, serve as guide-books.