This is very lucid clear book by my Guru Pujya Swami Dayananda Saraswati, that I recommend for all serious long-term students and teachers of Vedanta. This is because the teaching tradition of Vedanta is as important as even its vision of oneness - because the vision is dependent on the method of handling the words unfolding the vision.
You can buy the book both Kindle Version or a paperback on Amazon.