  Several principal aspects of a theoretical approach to the theory of
faster-than-light particles (tachyons) are considered in this note. They
concern the resolution of such problems of tachyon theory as the causality
violation by tachyons, the stability of the tachyon vacuum, and the stability
of ordinary particles against the spontaneous emission of tachyons, i.e. the
problems which are generally used as arguments against the possibility of such
particles. It is demonstrated that all these arguments contain nontrivial
loopholes which undermine their validity. A demand for a consistent tachyon
theory is formulated, and several ideas for its construction are suggested.
