Studio portrait of Landsturmmann Ernst Baum of 2. Landsturm Infanterie Ersatz Bataillon 'Hersfeld' (XI 29) and former employee of photographer to the Kaiser, Oscar Tellgmann. On the accompanying letter on the reverse, Landsturmmann Baum sends his best wishes to Herr Tellgmann on the occasion of his former employer's 58th birthday. Oscar Tellgmann specialised in royal portraits and taking photographs of the large military manoeuvres so enjoyed by the Kaiser and his senior officers. A comprehensive article on Oscar Tellgmann can be found on Wikipedia.
Studio portrait of Landsturmmann Baum and the letter on reverse.