Although I say advanced, it is really for anyone who desires TRUTH, and to reside in a deep sense of happiness, peace and love.
If one is open, willing and humble enough - it is surely available.
My Top 9 Books (out of a few hundred)
Top Books:
Autobiography of a Jnani: http://www.wearesentience.com/uploads/7/2/9/3/7293936/autobiography_of_a_jnani.pdf
Autobiography of a Yogi: https://www.amazon.com/Autobiography-Self-Realization-Fellowship-Paramahansa-Yogananda/dp/0876120796/ref=sr_1_1?ie=UTF8&qid=1516288435&sr=8-1&keywords=autobiography+of+a+yogi
Nisgardata Gita: http://prahlad.org/gallery/nisargadatta/NisargadattaGita.pdf
Gurunath Gita: https://www.amazon.com/Gurunath-Gita-Yogiraj-Siddhanath/dp/1484063724
Who Am I?: http://www.sriramanamaharshi.org/wp-content/uploads/2012/12/who_am_I.pdf
The Most Direct Means To Eternal Bliss: https://www.amazon.com/MOST-DIRECT-MEANS-ETERNAL-BLISS/dp/0979726786/ref=sr_1_1?ie=UTF8&qid=1516286618&sr=8-1&keywords=the+most+direct+means+to+eternal+bliss
Eternal Humans, Finite Gods: https://www.amazon.com/Eternal-Humans-Finite-Gods-Ex-Prophet/dp/099125404X/ref=sr_1_1?ie=UTF8&qid=1516286719&sr=8-1&keywords=eternal+humans+and+the+finite+gods
The Law of One:Book 1 of 5: http://www.llresearch.org/library/the_law_of_one_pdf/the_law_of_one_book_1.pdf