glimpses of world history

I just started reading 'Glimpses of World History' by Jawaharlal Nehru. In conjunction with 'Discovery of India' - these books are an essential component (IMO) of any Indian's library. What I am constantly amazed by, are the depth and breadth of knowledge that he had in his arsenal. He wrote the whole book as a series of letters to his daughter... from prison - with the aid of nothing but his pen and his mind... no library, no catalogs. In the event, it is a remarkable testament to the scholar... something I admire and aspire to emulate - regardless of what I think of his views on public policy.