  The Lorentz Transformation is derived from only three simple postulates:
  (i) a weak kinematical form of the Special Relativity Principle that requires
the equivalence of reciprocal space-time measurements by two different inertial
observers;
  (ii) Uniqueness, that is the condition that the Lorentz Transformation should
be a single valued function of its arguments;
  (iii) Spatial Isotropy.
  It is also shown that to derive the Lorentz Transformation for space-time
points lying along a common axis, parallel to the relative velocity direction,
of two inertial frames, postulates (i) and (ii) are sufficient. The kinematics
of the Lorentz Transformation is then developed to demonstrate that, for
consistency with Classical Electrodynamics, light must consist of massless (or
almost massless) particles: photons.
