“The Risen Christ and the Etheric Christ” is a booklet containing two lectures by Alfred Heidenreich, a leader of the so-called Christian Community, an auxiliary of Rudolf Steiner's Anthroposophical Society. The Community was formed by Friedrich Rittelmeyer. Heidenreich was responsible for the Community's international work, which may explain why the lectures in this pamphlet were given in New York, USA.
The lectures are rather short and very “in house”. I don't think they are of much interest, except perhaps for Anthroposophists. And even they might be disappointed, since Heidenreich only skims the surface when discussing “the return of Christ in the etheric”. For the real deal, read Sergei O Prokofieff's “The Mystery of the Resurrection in the Light of Anthroposophy” or Rudolf Steiner's original writings!