The Unknown And The Unknowable is the sequel to my debut book Our Universe An Unending Mystery published by Create Space, an Amazon Company in 2017. In the earlier book, knowledge frontier areas in the physical, spiritual, and occult worlds were identified and their interdependence was highlighted. The present book extends the thought process further into exciting arcane domains like time travel and wormholes in the physical world, religion-the eternal dilemma and the interpretation of dreams in the spiritual and occult worlds respectively. Aside from this, two new areas; The human life form and math conundrums have been added to make the review more comprehensive and interesting. The unique panorama of the human life form from womb to tomb is sketched with notes on the mysterious workings of major organs and glands. Unique human capabilities like the third eye, the use of languages for communication, proprioception, the reality or otherwise of free will and other abstract topics have been evaluated. The math conundrums have been cherry-picked: e.g. the zero discovery and the Ramanujan Magic Square make interesting reading. The book would be a useful addition to libraries wishing to highlight abstract topics.