21 August] 1853 – 4 April 1932) was a Baltic German chemist and philosopher.
He received the Nobel Prize in Chemistry in 1909 for his work on catalysis, chemical equilibria and reaction velocities.
Ostwald, Jacobus Henricus van 't Hoff, Walther Nernst, and Svante Arrhenius are usually credited with being the modern founders of the field of physical chemistry.