The founding documents of the field are public and verifiable. Hugo Münsterberg's 'Psychology and Industrial Efficiency' (1913) laid out the program of aptitude-based selection in English, and his 'Grundzüge der Psychotechnik' (1914) did so for German readers. William Stern's writings on applied psychology from 1903 onward supplied the term 'Psychotechnik' itself.
For the successor fields, Wojciech Jastrzębowski's 1857 outline of ergonomics predates the discipline's formal organization around 1949, and Alphonse Chapanis's post-war work on human engineering documents how wartime aviation research reshaped applied psychology. Standard histories of industrial-organizational psychology trace the renaming of psychotechnics after 1945 and the continuity of its methods.