Here is a link to an online read of a book actually written by Sri Nisargadatta Maharaj in 1963. Other Nisargadatta books are compiled quotes written down by others. I've just begun to read it.
Wow! I've read a good bit of it. Pretty intense and thorough. Hard to believe it's written by Nisargadatta. It seems different from his style of speaking and includes philosophy, methods of practice and devotion that don't remind me of his later words.
Hello I have to say that the lectures and lessons on the above site are some of the best i've come across yet. Adding this kind of self-investigation to my daily practice is becoming quite rewarding. click on "collected works" there and read some of the lessons when you have a moment to read. Robert Adams was a student of Ramana Maharshi and also visited Nisargadatta. Alan