As the opening song on T. Rex's epochal Electric Warrior breakthrough album, "Mambo Sun" holds a special place in the heart of every vintage Bolan fan. Certainly the opening lyric -- "beneath the bebop moon/I wanna croon with you" -- sounded like a personal pledge to every one of them, while the song's laid-back shuffle, the seemingly sketchy lyric, and the intakes of breath and off-mic animal yowls are as seductive as any of Bolan's period accomplishments: "I've got stars in my beard and I feel real weird for you." The feel of the song is rough, almost one-take-ish, and evidence suggests that it might well have been. No noticeably alternate versions have been unearthed, while the song is also conspicuously absent from either live or broadcast tapes of T Rex at their peak. A shame, because "Mambo Sun" is one of the most potent indications of just how high that peak would be.