A correction to one of Einstein's derivations of the Lorentz transformation

R.J. Hannon has described as "obscure" one of Einstein's derivations [Relat ivity: The Special and General Theory (Wings Books, New York, 1961)] of the special Lorentz transformation. That derivation does indeed contain an err or although it is an error of omission rather than of commission. The error is rectified herein by replacing 12 lines of Einstein's derivation. Two-by -two matrices are used in one form of this replacement. Another Part of his argument is made clearer in an endnote. As amended, Einstein's derivation becomes much clearer than his original one of 1905. To disarm some unjustifiable criticisms, and for further clarification, som e of the errors by a reviewer are mentioned in the endnotes.