Ah, Wizardry. This series, along with Ultima and the Might & Magic series were the early pioneers of the western-style RPG where the focus was more on the player and the elements of fantasy, more than walking through a story. However, the Wizardry series especially, had a great influence on later JRPGs, notably Final Fantasy and Dragon Quest. Wizardry: Proving Grounds of the Mad Overlord was originally released all the way back in 1981 on the original Apple II! The copies I have, however, came later on. The "PC" version that I have came later in 1984 and my Japanese PC-88 copy in 1985.
The game itself, given its age, is a very primitive first person dungeon crawler style game with the RPG elements one would expect from a game of this nature. Additionally, many of the game's elements are controlled through text options rather than through any sort of graphical elements. Even battles themselves are described through text and dialog rather than through anything visual. Perhaps disappointing by today's standards, but the game itself is quite compelling for its time and for its relatively simple nature.
The goal for this particular entry into the Wizardry series is to explore the dungeon, collect treasure and gain experience to learn new skills, exactly like later titles in the RPG genre. Like many games, the primary goal is to defeat the arch-wizard who is, of course, the final boss.
If you're looking to see the roots of one of the most wildly popular game genres of all time, it's hard to beat Wizardry.