The Transylvanian Hungarian Historical Dictionary is an outstanding piece of work even within Attila T. Szabó's oeuvre of unparalleled dimensions. In his various accounts of his own life and scholarly activities, he regarded that dictionary as his chef-d'oeuvre himself; as time passed, he increasingly concentrated his attention, thought and energy on it. Among his many other superb achievements, this was the work that commanded attention in professional circles to an exceptional extent, calling forth a number of detailed reviews and analyses as well as favourable recognition from all quarters, linguists and representatives of neighbouring disciplines alike. (The dictionary is still being edited and published, Volume 13 is forthcoming soon.) This talk presents Attila T. Szabó's life and work, including personal memories of the speaker, with the Dictionary in the focus of attention. Its national and international significance is briefly discussed and its interdisciplinary character is emphasized.