physicist and pioneer in German wireless telegraphy (telegraph).

Slaby studied at the Berlin Trade Academy and the Royal Trade School in Potsdam and from 1883 until 1912 taught at the Technical High School at Charlottenburg. Inspired by Guglielmo Marconi (Marconi, Guglielmo)'s electromagnetic-wave experiments, he introduced resonant coils, known as Slaby rods, for the measurement of wavelengths. In collaboration with Georg von Arco and Marconi, he helped develop wireless telegraphy in England. Slaby subsequently proposed the Slaby–Arco system—a modification of Marconi's antenna that, with the Braun and Siemens–Halske systems, was adopted by the German wireless system established in 1903.