He is remembered for his research in the field of parapsychology. He published numerous books and articles on topics such as telepathy, spiritualism, telekinesis, etc. He was inspired by the British Society for Psychical Research, and with philosopherTraugott Konstantin Oesterreich tried to establish a similar institute in Germany. With Albert von Schrenck-Notzing, he fought for the recognition of parapsychology as a serious subject of study. Among his most important contributions to the field of parapsychology were his experiments in clairvoyance, conducted at a time when most such research concerned telepathy. These experiments involved selected participants in identifying the targets - typically, text or drawings - concealed in opaque envelopes, while no persons were aware of the contents of the envelope. Tischner's monograph Telepathie und Hellsehen collected his reports on these studies. In this work, Tischner referred to telepathy and clairvoyance as instances of a more general faculty of Außersinnlicher Wahrnehmung, thus, in its translation, coining the term extrasensory perception. Tischner performed research on the possibilities of merging homeopathy with evidence-based medicine, and published a book on the evolution of homeopathy named "Das Werden der Homöopathie". He was the author of works on homeopathSamuel Hahnemann, titled "Samuel Hahnemann's Leben und Lehre" and "Die Bildwerke Hahnemanns und ihre Schöpfer". In the field of hypnosis he produced writings on the life and work of Franz Anton Mesmer, called "Franz Anton Mesmer, Leben, Werk und Wirkung" and "Mesmer und sein Problem, Magnetismus, Suggestion, Hypnose".
Selected publications
Das Werden der Homöopathie: Geschichte der Homöopathie vom Altertum bis zur neuesten Zeit, 9 editions published between 1950 and 2001 in German
Einführung in den Okkultismus und Spiritismus ; J. F. Bergmann, München, 1923; 11 editions published between 1921 and 1923 in German
Ergebnisse okkulter Forschung, eine Einführung in die Parapsychologie ; Wissenschaftliche Buchgesellschaft, Darmstadt 1976; ; 26 editions published between 1950 and 1976 in 3 languages
Fernfühlen und Mesmerismus 9 editions published in 1925 in German
Franz Anton Mesmer; Leben, Werk und Wirkungen 11 editions published in 1928 in German and English
Geschichte der homöopathie 16 editions published between 1932 and 2013 in 3 languages
Geschichte der okkultistischen Forschung ; Pfullingen, 1924
Geschichte der Parapsychologie, Teil 2 ; Pustet, Tittmoning, 1960
Mesmer, Franz Anton, Über telepathie und hellsehen; experimentell theoretische untersuchungen 16 editions published between 1920 and 1921 in German
Mesmer und sein Problem: Magnetismus, Suggestion, Hypnose 7 editions published in 1941 in German
Monismus und Okkultismus ; O. Mutze, Leipzig 1921
Telepathy and clairvoyance,17 editions published between 1925 and 2013 in English
Über Telepathie und Hellsehen, Experimentaltheoretische Untersuchungen; Bergmann ; München, 1920