The possibility that humans are not alone in the Universe and might in the future come in close contact with other intelligences is one of the most intriguing questions of human history and has deep implications for our understanding of the Universe and ourselves. In this book the subject is dealt with in an interdisciplinary way, giving the scientific and technological implications, discussing the philosophical and religious connotations and rebuffing the pseudo-scientific statements.

Based on our current scientific understanding of the Universe, the possibility of extraterrestrial life is discussed, summarizing cosmic, chemical and biological evolution. What we now know of the Universe suggests that life is common and extraterrestrial intelligent life is a possibility.

The problem of searching for extraterrestrial intelligent beings is often reduced to radiotelescope technology or the possibility of decoding a possible message. In many cases the idea of ETIs is loaded with anthropomorphism. The author discusses problems such as: what is intelligence? What is consciousness? Should we expect ETIs to be conscious beings and other philosophical issues. The future perspectives for humankind opened by long range spaceflight are also examined and the possibilities of true contact with other intelligent beings are considered.

At the heart of this book is an examination of the viability of future astronautics which would enable closer human contact with ETI than through radio messages taking thousands of years to reach their destination. The possibility of faster-than-light space travel is considered.

The book addressesreaders with an interest in general science, but also those with a humanist background, interested in the great philosophical debate about human nature, in particular the question of whether there is other intelligent life in the Universe, and the author counterbalances recent theories such as "rare earth".