Progressive rock and heavy metal borrowed heavily from each other throughout the 1970s and '80s, and some artists like Deep Purple and Lemmy Kilmister of Hawkwind and Motorhead dabbled in both. But while both genres shared an interest in extreme technical precision and quick tempos, the similarities ended there, as metal maintained a defiantly rebel stance while prog sought mainstream approval with its focus on complexity over speed. It wasn't until the mid-'80s that Seattle's Queensryche would effectively blend both elements. That group's imaginative lyrics and complex song structures were distinctly progressive, while its image and attitude remained palatable to metal fans. Queensryche's 1990 album Empire spawned a Top Ten single, "Silent Lucidity," paving the way for other progressive metal acts like King's X to receive heavy rotation on MTV and commercial radio. However, prog-metal's odd time signatures, theatrical lyrics, and exploratory song structures would not survive the grunge revolution, and with the exception of revivalists Dream Theater, it was relegated to the extreme outskirts of popular culture by the mid-'90s. But in the twenty-first century, a new wave of bands like The Mars Volta and The Dillinger Escape Plan favoring sonic complexity and metal atmospherics offered testimony to the enduring influence of progressive metal.

Notable Artists: Queensryche, King's X, Skyclad, Symphony X, Galactic Cowboys