This fascinating book on cosmology straddles the worlds of science and science fiction, addressing questions like the nature of time, e.g. Can it run backwards?, multiple realities and the possibility of the multiverse or infinite universes. Part One, The Nature Of Reality, considers regions of the universe where time may run backwards, infinite realities, wave functions and matterwaves plus a stuff or entity called ortho-positronium. Part Two, The Nature Of The Universe, considers invisible galaxies, stars and planets, mirror matter, the interaction between ordinary and mirror matter, black holes and their significance in the model of the universe, the possibility of intelligent life creating a universe and even how to build a universe. Relativity, quantum physics, the ideas of Hoyle and Chandrasekhar and many others are involved in the speculations. Part Three discusses the likelihood of life on earth having been seeded from space, the comet connection, life as a cosmic phenomenon and the strong possibility of finding alien artefacts on the earth and the moon. The book concludes with a glossary of terms, a reading list with separate headings for Fiction and Non-Fiction and a thorough index. It is a stimulating and thought provoking read written in a manner that everyone can understand. I highly recommend it.