Lost Worlds is a novel little gamebook series created by Alfred Leonardi. They’ve been published by several company’s over the years, but Nova was the first in 1983. They’re a hand-to-hand combat variant of rules Leonardi created for the Ace of Aces dogfighting game in 1980 (which are super cool in their own right and I need to share them with y’all some time)

These are combat books and totally modular, so you can pick your favorite fighter in the line and square them off against any other fighter, or monster. You can even party up 2 or 3 on one for tough monsters. When you play, you hand your character book off to you opponent — the pages inside are their first person view of you character attacking. You choose maneuvers from a card and resolve them simultaneously. Sometimes they result in you scoring a hit or being hit, other times you’ll whiff or reposition. Most of the time, a given move you select and the move your opponent used restrict your options for the following turn — getting knocked down is going to make it hard to charge next round, for instance.

This is a pretty standard human fighter type — Barbarian with Two-Handed Sword (who looks vaguely like Alan Moore?).