According to me, if you are in your early twenties and looking for some enlightening books, you must read following books. I strongly believe ten years from now, you will attribute a lot of your success to some of these books. Having read all of them and being influenced by every one of them, I call myself fortunate that I had a company of these great books when I needed them most. I have given online link of every book from where they can be purchased.
I hope you find them useful.
Best wishes.

Wings of Fire: An Autobiography 1st Edition – If you are an Indian, in your early twenties then you must read this book.
This book is an autobiographical novel that tells the  readers a story about unlocking their inner potential. APJ Abdul Kalam does a  great deal to throw light on his journey to igniting the fire within  himself. This book is divided into seven parts. This is then followed by an Orientation, which  contains a quote from the Atharva Veda. After that, the readers are  also enlightened on the incidents that made Kalam what he is today.

• Unposted Letter – is a collection of short articles that contains deep and profound  reflections on many topics related to life, work, situations, and  attitudes. Each page contains ideas and concepts that can change your view on many things and make your life richer and more  enjoyable. A good read recommended for young readers.

 

• Letters From a Father to His Daughter – These letters reflect on a variety of topics. Starting from  natural history, the beginning of the earth, and evolution to the varied races of the world, the genetic make-up, the  differences in communities, and races, how these races were formed, and  why people look different. Book also touches upon the topic of civilizations. It discusses the  ancient civilizations, the great cities of ancient times, the origin of  language and religion, the growth of mankind, and the changes in  religion and its current manifestations. Nehru also elaborately  discusses the history of India, the Ramayana, the Mahabharata, and the  great kings of the past and their kingdoms.

 

• I Too Had a Dream –  You must read about Dr. Verghese Kurien in your early young age. Dr. Verghese Kurien is father of white revolution and is the man behind success of Amul Dairy. For more information read my blog about the book: I too had a dream. — Dr. Verghese Kurien

 

• Gitanjali – One of the greatest writers in modern India, Rabindranath Tagore became  the first Indian to be awarded the Nobel Prize, which he received for  his outstanding contribution to Literature. Known for his elegant prose  and magical poetry, Gitanjali captures the essence of Tagore’s poetic  spirit. The poetry of Tagore is soothing to the spirit of the  person who reads it. These poems look at the deepest and the most  spiritual aspects of life with a simplicity and grace that touch your  soul. They encourage you to look at the world around, in a fresh light,  and experience the beauty of creation.

 

Siddhartha – Siddhartha’ is a novel by Hermann Hesse which deals with  the spiritual journey of an Indian boy called Siddhartha during the time  of the Buddha. The book was written in German, in a simple, yet  powerful and lyrical style. It was first published in 1922, after Hesse  had spent some time in India in the 1910s. The story revolves  around a young man who leaves his home and family on a quest for the  Truth. Embarking on a journey that takes him from the austerities of  renunciation to the profligacy of wealth. That leads him through the  range of human experiences from hunger and want, to passion, pleasure,  pain, greed, yearning, boredom, love, despair and hope. A journey that  leads finally to the river, where he gains peace and eventually wisdom.  This is the story of Siddhartha as told by Nobel Laureate Hermann Hesse  in his most influential work.