Chakravarti Rajagopalachari, informally called Rajaji or C.R., was an Indian lawyer, independence activist, politician, writer, and statesman. Rajagopalachari was the last Governor-General of India. He also served as leader of the Indian National Congress, Premier of the Madras Presidency, Governor of West Bengal, Minister for Home Affairs of the Indian Union, and Chief Minister of Madras state, and as such, he rendered yeomen service to the nation.
Rajagopalachari founded the Swatantra Party and was one of the first recipients of India's highest civilian award, the Bharat Ratna. He vehemently opposed the use of nuclear weapons and was a proponent of world peace and disarmament. During his lifetime, he also acquired the nickname 'Mango of Salem'.
Rajaji was a great patriot, astute politician, incisive thinker, great visionary, and one of the greatest statesmen of all time. He was a close associate of Mahatma Gandhi, hailed as conscious-keeper of the Mahatma.
Rajaji was closely associated with Kulapati Munshiji and he was among the distinguished founder-members of the Bhavan (Bharatiya Vidya Bhavan). The Bhavan has published 18 books by him so far, the copyright of which he gifted to the Bhavan. Rajaji wrote not only in English but also in chaste Tamil, his mother-tongue. He was at his best as a short-story writer.
This is a lovely little introduction to the main teachings of the Upanishads.
C. Rajagopalachari introduces the Upanishadic teachings for the children. This si what he says in the introduction and in many parts of the books. Of course, it is written in a simple language. But the themes are very profound - It is about the Paramatma/Brahma and how we can come to know It. IT is within us and within each of the objects (both animate and inanimate) in the world. When we are able to realize it, and as a result when we see the Brahman in every person and every object we will be released from the circle of life. We will attain the Moksha.
The desires and attachments block us to realize this very simple fact. We need to get rid of the desires and attachments and thus need to free our mind to see the TRUTH. But the soul/Atman often loves to be in the ignorance caused by the attachments.
The real Upanishadic fact is explained through many similes. These similes are taken from the Upanishads themselves.
An Example:
How can we say that everything and every person is from the Brahman? The tiny seed of the banyan when it is split contains nothing. But it is this nothing which holds in itself the vast tree with its branches, leaves, and fruits.
How can we say that the Brahman is present everywhere in the world? Take for example a piece of salt. Drop it in a glass of water. Look for it after sometime. It is no more there. But the water has become salty containing the salt in some form. Pour out the water down. Can we say that the salt is lost. No, it remains somewhere in some form.
Note: A Simple training in Indian philosophy will help you to appreciate the book all the more. I think, the English translation of the book is also available. Look for this one: Upanishads.