Rabbi Shlomo ben Adret, known to his student by the acronym of his name Rashba, was one of the most brilliant Talmudists of medieval Spain. Student of Nachmanides (Ramban) and teacher to the Ritva, his writings are studied to the present day.
Here’s Dr. Abramson in print (because there are times and places where one just can’t enjoy a video). Check out the eBook versions as well.