Instead of blindly following popular preconceptions and biases about matters that we have not yet had the chance to test or verify, examined in this volume is our current state of knowledge, as well as our present state of ignorance, on subjects related to interstellar travel. The science and technology of the future that would be available for building interstellar space ships would indeed be quite different from those imagined from the perspectives of the early twenty-first century. Nevertheless, it is a good idea to start thinking what it will take to mount such an undertaking so that we can begin exploring various scientific and engineering possibilities now -- rather than wait endlessly for 'the right time' to come.