'Sweet Emotion' by Aerosmith earns the top spot on our Top 100 Classic Rock Songs list by embodying such an overwhelming portion of the intangible things that make the rest of the songs on our countdown so timeless. It also rocks to high heaven.

With that famously hypnotic yet somehow menacing opening bass riff, effortlessly interlocking and alternating "smooth" choruses and "crunchy" verses, Steven Tyler's highly evocative but never fully revealing lyrics and that bashing, reportedly improvised uptempo coda, 'Sweet Emotion' has defended its spot atop classic rock radio airplay lists for nearly four decades.

Attitude, style, wit, peer inspiration and the collaborative skills of a unified, creative group of hungry musicians all played a part in the creation of this eternal classic, and an exclusive conversation with bassist and main 'Emotion' songwriter Tom Hamilton shed some interesting light on the process.

Hamilton's not sure if he did indeed write that beautiful bass line and the beginnings of the song back in high school, as some reports have stated: "That little period tends to kind of run together. It's very possible. But it was right around that period, and I sat down, you know, got myself in my favorite state of mind. What usually happens is, I'll sit down to practice, and do some physical-type calisthenics to get the joints and the muscles all warmed up. My mind starts to drift, it's almost like a daydream, like a river flowing by, little things pop out of the river, that I start playing. If it's something that I really like, I remember it. So I came up with the little piece that's the intro of the song, on the bass, and I just kept going from there."

He also credits guitar legend Jeff Beck for inspiring his songwriting: "One thing that was going on, which leads me to believe that I first came up with (the song) when we first moved in together -- we all lived together on 1325 Commonwealth Avenue -- we used to listen to this Jeff Beck record called 'Rough and Ready.' It was a very cool, jazz-funk-rock type of album. Without learning any of the parts from that, I wanted to do something that evoked the feeling I got from it. I picked up a guitar and wrote some parts that went along with the bass parts, and just kept it in the back of my mind."

Which is where it stayed for a little while. "I think at one point during the sessions for our second album, (1974's) 'Get Your Wings,' I showed Steven what I was working on. He was busy, so he didn't pay all that much attention to it, but he did make a couple of suggestions. Finally, on our third album (1975's 'Toys in the Attic'), we had gotten to the point where we finished all of our basic tracks. We had an extra day left over, and our producer Jack Douglas, who is also producing our new (2012, as yet untitled) album, asked if anybody had any extra riffs lying around. I started to show it to everybody, and by the end of the afternoon, I kinda showed everybody the parts, we were jamming on it, and refined it into the arrangement that became 'Sweet Emotion.'

If you're trying to figure out exactly how Hamilton got that exotic sound for his bass intro, you should know there's some unique percussion involved. A bass marimba, similar but deeper in tone to the version of the instrument simulated on the ubiquitous default iPhone ring tone, also appears on the track. "Our engineer, Jay Messina, is a vibes player, so they had this crazy idea of doubling the bass part with a bass marimba, to give it sort of a more mysterious sound. It's funny, cause it really messes people up who are trying to learn the song off the record."

Hamilton then exited the process: "We were on a super-tight budget, so we would get the basic tracks done, then there wasn't a lot left to do for (drummer) Joey (Kramer) and (guitarist) Brad (Whitford). So we would split, and go home to Boston while Joe (Perry) and Jack and Steven stayed in New York. And that's when Steven would write the vocals to the songs. We very rarely knew what was going to be sung over these arrangements.

In fact, Hamilton didn't even know the song would be called 'Sweet Emotion' at this stage. "We knew which section was going to be the verse, the chorus, and the bridge, but we didn't have any lyrics, melody or anything. So it was a really amazing phenomenon where Joe and Steven would come back to Boston, a month and a half, two months later, with all the songs written, with all the vocal parts. It was... just unbelievable, when I first heard 'Sweet Emotion' with the lyrics on it. I thought 'Wow, that is unbelievable.'"

The bassist modestly says the track "became one of our fan favorites," when in reality it was Aerosmith's breakthrough single, paving the way for 'Attic''s other massive hit, 'Walk this Way' and the successful re-release of the initially under-performing ballad 'Dream On' from the group's first album.

"It's a style of putting a song together that I still love, which is keeping the basic structure very very simple, you know, maybe three parts. Once you get those recorded, then you can start hanging ornaments off it, like a Christmas tree, make it something more elaborate and sophisticated. That's the same kind of style that I used to come up with a couple of tracks for the new record."

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Watch Aerosmith Perform 'Sweet Emotion'