In late 1968, Led Zeppelin began pioneering a heavier, more metallic-sounding form of rock geared for FM radio's new album-oriented stereo format. By combining a slashing electric guitar and wailing vocals with a rhythmic bass and locomotive drums, the band quickly became the darlings of better stereo systems and large indoor arenas—and inspired several generations of metal-driven rockers.

When "Whole Lotta Love" was released in October 1969, it appeared first on "Led Zeppelin II," the band's second album,...