The Isley Brothers’ most successful and most influential album opens with a punch in the mouth: “Fight The Power” hits immediately with a ferocious, driving groove and vocal utterances that make it sound like the Isleys are literally in the middle of a fistfight. By the time Ronald intones the radio-unfriendly “bullshit”—which couldn’t keep the single from reaching No. 4 on Billboard’s Hot 100—in the song’s chorus, any listener will be ready to dance right through a wall (for justice, of course). Public Enemy certainly were when they interpolated the hit on their iconic 1989 single of the same name, extending the lineage of a song that will be relevant as long as unfairness exists. That’s just the opening of the Isley Brothers’ third straight platinum album: The rest of the release is divided exactly in half between sprawling funk jams and sprawling, seductive quiet storm ballads, two sides of the Isley canon that have always existed in tandem. The group is at the height of their powers on this release, as deft at crafting civil rights anthems and proto-disco dance-floor hits as timeless love songs—all of which have, in retrospect, proven massively influential. “For the Love of You” features Ronald at his silkiest, while “Make Me Say It Again Girl” is an unlikely hip-hop cornerstone, sampled in songs as disparate as “Hip Hop Hooray” and “Tha Crossroads” all before Beyoncé helped bring it back to the charts in 2022. The Heat Is On lives up to its title, a simmering, bubbling cauldron that is fiery and steamy at once. The Isley Brothers’ virtuosic musical efforts, their gurgling basslines and Hendrix-esque guitar solos and soaring vocal runs never obscure their depth of feeling; what they created together is one of the most important and still underrated albums of the decade.