Rod Argent flaked on our 9 a.m. interview, so we're starting 90 minutes later than scheduled. The revered Zombies keyboardist/songwriter said he was working on a new song and forgot about the time. (That old alibi?)

Whatever the case, it's impossible to be angry with Rod Argent. He may be 68 and occasionally absentminded, but he's perhaps the jolliest, most upbeat person I've interviewed in 30 years. An absurdly high percentage of his words bubble forth buoyed by hearty chuckles, and his dulcet, expressive voice makes everything he says seem utterly fascinating (and much of it is).

Argent has ample reason to be cheerful. He wrote three of the Zombies' biggest hits—"She's Not There," "Tell Her No," and "Time of the Season"—all of which deserve heavy rotation on eternity's jukebox. (The latter has been sampled more than a dozen times by hiphop and electronic-music producers.) Adept with classical and jazz music as well as rock, he also cowrote (with former Zombie Chris White) the British prog-rock band Argent's massive 1972 smash "Hold Your Head Up."

Rod Argent is a wealthy, canonical rock artist, yet he's still hungry to create new music. He and honey-toned Zombies singer Colin Blunstone and former Argent bandmates (but not White, who's retired from the stage) are taking a well-deserved victory lap 45 years after the Zombies initially split due to the demoralizing commercial failure of their all-time classic album Odessey and Oracle (#100 in Rolling Stone's 500 Greatest Albums of All Time poll, if you're keeping score).

In retrospect, it's hard to believe how dense 1968 humanity was that it couldn't instantly, madly love Odessey and Oracle. It took more than a decade, but the album began to gain traction with an increasing number of Brit-pop aficionados, including Paul Weller, who declared OAO one of his favorite LPs of all time when he was writing his own hits with the Jam.

During their initial peak run (1964–1969), the Zombies made the Beatles seem like the Rolling Stones. In other words, they had little raw animal magnetism, but plenty of choirboy charm and bookish suavity—the proverbial nice-bloke group. While these Englishmen loved covering songs by black American musicians, they didn't really convince in this style. Rather, as Odessey and Oracle indisputably proved, the Zombies excelled at ornate pop that carried an almost liturgical aura. See "Changes" for the zenith of this approach. Unfortunately, the complexly layered vocal harmonies need more people than is feasible to execute on this tour. Similar issues sadly prevent the unbearably poignant "Brief Candles" and the sublimely flowery "Hung Up on a Dream" from getting aired.

Powered by White and Argent's nuanced song structures and nutritiously sweet melodies and Blunstone's hushed, devotional vocals, Odessey is the rare album that still invigorates after a hundred-plus listens. It's impossible to exhaust the exquisitely ebullient and melancholy pleasures of this masterpiece—well, except for "Butcher's Tale (Western Front 1914)"; that one can be skipped with no tears.

While 99.7 percent of Bumbershoot attendees likely just want the Zombies to do their '60s classics, Argent stresses more than once that "the last thing we want to do is just go out there and do nothing else but be a nostalgia band. We honestly enjoy rediscovering the old canon and doing stuff that maybe we didn't even play live the first time around." He adds that they'll be improvising when possible and playing four songs from the Zombies' 2011 album Breathe Out, Breathe In. Don't fret, though: Most of the Bumbershoot set will focus on the hits and almost half of Odessey, as well as "Hold Your Head Up" and a handful of Blunstone solo cuts such as "I Don't Believe in Miracles" and "This Old Heart of Mine."

Many Zombies tunes, Argent says, "have a bit of improvisation in them, and it means we can vary them a bit each night and not just go through the motions. We try to shape and move things forward. In our minds, that gives us a feeling of legitimacy a bit more and a fresh energy."

Unlike many aging rockers, Argent and Blunstone haven't let their skills wither. "Colin made a point from the late '90s onward to do vocal exercises every day," Argent says. "You don't have to lose your chops, but you have to work at it if you're not gonna do that as you get older. Colin has always worked on his. We do everything in the original keys, always."

You can attribute Argent and Blunsone's suppleness partially to clean living. Argent claims that the Zombies largely eschewed drugs, although they did enjoy their liquor. "I've never had anything against people taking drugs, but it's never particularly interested me," Argent says. "It always felt like a fairly crude mechanism to me. The original Zombies broke up in 1967—up until that time, apart from an occasional bit of marijuana, people I knew had no knowledge of drugs. It was maybe from '67 onward, LSD first came into prominence. We broke up just as drugs started to become important."

"I think I can play better now than I could then. I can sing better now than I could then. Some of that survival of ability and chops has something to do with—thank you, somebody out there—that I'm not damaged."

Surely when the Zombies went supernova, they indulged in some extravagant activities. Right, Rod? "I'm not prepared to tell you, really," Argent says, laughing.

Oh, come on. "No, no, no. No. No. All I'll say on the drugs side of things is we didn't indulge to excess. Like everybody else, we would always drink too much. That was just a fact of being on the road—never to a point where it was a problem. Maybe none of us had an addictive personality, so it never got to the point where it was a problem."

Let's hear some tales of debauchery, man. Statute of limitations and all that. He chuckles, "No, I'm not going to tell you."

Well, maybe they get into a bit of mischief now? Um, no. "What you can't do is burn the candle at both ends as you get older," Argent affirms. "When we finish a concert, Colin and I are ready just to wind down and go back to the hotel. We feel that we have to conserve our energy. But onstage, the energy is 100 percent."

Okay, let's talk about something wholesome, like Argent's Mellotron sound, which sacralized so much of Odessey and Oracle. How did he get it to resonate so differently compared to the Moody Blues and the Beatles? "Well, I don't know. As I remember it, we walked into Abbey Road Studios virtually as the Beatles were walking out, having just done Sgt. Pepper's. Lennon left his Mellotron in the studio. We thought, 'We'll have a bit of that.' [Laughs] I just used the sounds that were there. There were only a few presets on there. Maybe I chose the ones that McCartney and Lennon didn't use."

We haven't talked much about Argent, Rod's ambitious post-Zombies prog outfit. When you dig beyond "Hold Your Head Up" and the Kiss-covered "God Gave Rock 'n' Roll to You," you discover a catalog teeming with some incredibly complex, weird excursions worthy of your begrudging respect. "We always tried to do our own thing and not be commercial for its own sake," Argent says. "Which is actually true for the Zombies, as well. Right at the beginning with the Zombies, we were progressive in the sense that we never thought we've got to repeat what we've just done. We never thought we had to get to the hook in 30 or 40 seconds. We always just tried to work on ideas. 'Hey, that sounds unusual and fresh. Let's work on that and see where it goes.'" And it usually goes somewhere very pleasant.

Want to hear something funny? Argent and Blunstone have never seen a zombie film.