Ian Anderson was finishing up an interview about the first Jethro Tull album in almost two decades, 2022’s The Zealot Gene, when he offered GRAMMY.com some tantalizing news: the next one would arrive sooner rather than later.

"At 9 o'clock on the first of January, I will open my mind and heart to the visiting muse," Anderson said two weeks before the end of 2021. "Should she decide to visit — hopefully, by 10 o'clock, I'll have the beginnings of some kind of flicker of an idea." 

Where might Anderson, a voracious reader with a sweeping purview and a learned, gentlemanly air, go from there?

Fast forward to today, and we have the result: RökFlöte, which arrived April 21 and is based on "the characters and roles of some of the princip[al] gods of the old Norse paganism."

The GRAMMY-winning prog-rock heroes’ catalog has always been flecked with similar mythology, especially on 1977's fantastical, bucolic Songs From the Wood. But never had Anderson dedicated an entire album to this specific system of concepts.

RökFlöte’s opener, "Voluspo," is titled after the most famous poem in the Poetic Edda, which dates back centuries. Lead single "Ginnungagap" refers to the bottomless abyss that encompassed all things prior to the creation of the cosmos. "Ithavoll" is the meeting place of the gods.

This sheer depth of reference is not new for Anderson and company. A band less cited for their musical and philosophical depth than mined for cheap codpiece and Anchorman jokes, Jethro Tull contain multitudes just beneath the surface.

Take a stroll through the band's discography, and you'll find Anderson doesn't linger on one topic for long — and often addresses many concepts within the same album, or even song. Even Tull's most straightforward hits often contain richer meaning than what immediately meets the ear. 

To celebrate the release of RökFlöte, here's a by-no-means-comprehensive breakdown of the poles Anderson and crew have tended to touch on throughout the band' almost 60-year career.

Love (With Some Caveats)

"I am a descriptive writer," Anderson wrote in the preface to his career-spanning compendium of lyrics, Silent Singing. "Not so often a storyteller, and almost never a heart-on-sleeve love-rat. Social documentary that you can hum along to." 

True, this applies to the lion's share of his songs. But there are a couple of major exceptions — perhaps ones that prove the rule. 

Take "Wond'ring Aloud," his gorgeous acoustic ballad on 1971's Aqualung that clocks in at less than two minutes. If there's any kind of social commentary or obscure meaning in "Wond'ring Aloud," it's difficult to tease out. Rather, the tune unfurls a quiet, domestic tableau of romantic bliss: 

"Last night sipped the sunset/ My hand in her hair," he sings. "We are our own saviors as we start/ Both our hearts beating life into each other." The aroma of breakfast wafts through the kitchen; he considers their years ahead. Then, the unforgettable closing line: "And it's only the giving that makes you what you are."

Flash forward to "One White Duck / 0¹⁰ = Nothing at All," another gobsmacking acoustic-with-strings centerpiece, from 1975's Minstrel in the Gallery.

Online chatter seems to suggest that the image of "one white duck on your wall" refers to a domestic split. Whatever the case, the darkly romantic song is suggestive of packing and leaving: "There's a haze on the skyline to wish me on my way/ There's a note on the telephone, some roses on a tray." From there, the song unfurls into a litany of images, commensurately puzzling and evocative — and full of arcane British-isms.

Like every other arena of life represented in Jethro Tull songs, romance comes with bottomless shades and nuances — and Anderson's seemingly attuned to the full spectrum.

Religion (As A Nonbeliever)

Jethro Tull classics that address faith, like Aqualung's "My God," "Hymn 43" and "Wind Up," excoriate religious corruption and dogma — to the degree that Anderson comes across as defensive of God.

"It's about turning God into a vehicle for personal power and the glitz and paraphernalia that sometimes surrounds religion," Anderson wrote of "My God" in 2019's oral history of the band, The Ballad of Jethro Tull. "It's actually quite pro-God in asking: 'People what have you done/ Locked him in his golden cage?'"

In "Wind Up," he rails: "I don't believe you/ You have the whole damn thing all wrong/ He's not the kind you have to wind up on Sundays." But it's crucial to stress that Anderson is decidedly not a man of faith.

Read More: Jethro Tull's Aqualung At 50: Ian Anderson On How Whimsy, Inquiry & Religious Skepticism Forged The Progressive Rock Classic

"I've learned to describe myself as somewhere between a pantheist and a deist," he wrote. "I'm not a Christian, but I like to do things for the church. I've always believed there are certain aspects of our society that, while anachronistic, are still worth preserving."

In an Olde English font in the Aqualung sleeve, Anderson printed a facsimile of Genesis 1:1: "In the beginning Man created God; and in the image of Man created He him." 

Of the religious commentary scattered throughout Tull's discography, none seem to summarize Anderson's views like the above.

Nature (The Non-Human Kind)

Jethro Tull's so-called "folk trilogy" in the late 1970s — Songs From the Wood, Heavy Horses, and Stormwatch — address the natural world from three different angles.

Songs From the Wood is drenched in the atmosphere of the English countryside, where “fairytale creatures, ley lines, naughty equestriennes and the pre-Christian era old gods all came to call," Anderson writes in Silent Singing. The jangling "Jack-in-the-Green," about a raggy character somewhere between a hobbit and the wizard Radagast, is one irresistible highlight.

The majestic Heavy Horses is something of a song cycle about animal life. The serrating opener "...And the Mouse Police Never Sleeps" nails cats, with evocative lines including "Claws that rake a furrow red/ License to mutilate" and "Windy rooftop weathercock/ Warm-blooded night on a cold tile." From there: dogs, moths, weathervanes, the passing of equine generations.

While Stormwatch's compartmentalization as a "folk album" is somewhat suspect — only "Dun Ringill" really fits the mold — it's spiritually connected to Songs From the Wood and Heavy Horses on that conceptual front.

Anderson had addressed climate change before, as on "Skating Away on the Thin Ice of a New Day" on 1974's War Child. ("Predicated on the then-mistaken belief, in popular science circles, that we were headed toward another ice age," Anderson writes in Silent Singing.)

The gloomy Stormwatch takes that theme all the way home; the 1979 album draws its power from the weather and the ocean — as well as paranoia about humanity's bludgeoning impact on it.

As jabs at Exxon and their ilk go, "North Sea Oil" is up there with Neil Young's "Vampire Blues." The heavenward "Orion" is an awestruck gaze at the celestial panorama. And "Dun Ringill" warns "The weather's on the change/ Ice clouds invading and pressure forming."

Nature (The Human Kind)

Anderson may write his songs like a documentarian, but he’s arguably at his most powerful when writes from the human side of the equation.

Their barreling hit “Locomotive Breath,” from Aqualung, is about runaway population growth, through the lens of an “all-time loser” on a brakeless train, “headlong to his death.”

Thirteen tracks into Tull's 1972 odds-and-ends album Living in the Past is their deep cut to end all deep cuts: "Wond'ring Again." A sequel to "Wond'ring Aloud," it's about as angry and voluble as the band ever got.

"The excrement bubbles, this century's slime decays/ And the brainwashing government's lackeys would have us say/ It's under control and we'll soon be on our way/ To a grand year for babies and quiz panel games," goes just one of its dizzying lines.

But Anderson’s perspective isn’t always from a 50,000-foot view. In other tunes, he cuts to the chase regarding what makes humanity tick.

Read More: Ian Anderson On The Historical Threads Of Fanaticism, Playing Ageless Instruments & Jethro Tull's New Album The Zealot Gene

A goof on what Anderson perceived as bloated concept albums of the day, the narrative of 1972's one-song album Thick as a Brick flows in all directions. Yet the opening salvo, titled "Ready Don't Mind" on later editions, is especially incisive in its needling of small-minded biases.

"I may make you feel, but I can't make you think," Anderson declares amid the backdrop of "the sandcastle virtues… all swept away/In the tidal destruction, the moral melee."

On "Aqualung," Tull's classic portrait of a seedy, streetbound derelict, Anderson zooms in on how the straights perceive this loathsome character.

"[It's] more in terms of our reaction to the homeless," Anderson explained to GRAMMY.com in 2021. "I felt it had a degree of poignancy because of the very mixed emotions we feel — compassion, fear, embarrassment. It's a very mixed and contradictory set of emotions."

Anderson’s reflections on human nature and the social order are not always that heavy; 1976's underrated Too Old to Rock 'n' Roll: Too Young to Die! explores "the cyclical nature of fashion, music and youth culture" through the lens of a hapless, aging protagonist, trapped in the mire of his youthful interests.

The American rocker in "Said She Was a Dancer" from 1987's Crest of a Knave is similarly over-the-hill, as he flirts with a disinterested Muscovite. What a clash between "Eastern steel and Western gold": "You've seen me in your magazines, or maybe on state television," he complains. "I'm your Pepsi-Cola, but you won't take me out the can."

From here, you can open Silent Singing and head in any direction — horny Tull ("Kissing Willie," "Roll Yer Own"), tech-curious Tull ("Dot Com"), and even odes to household objects ("Wicked Windows," about eyeglasses.)

If you're already a Tull fan, chances are a dozen more examples of these umbrella concepts have already popped into your head. If you're a newbie, you've stumbled on one of the most eclectic, intelligent, criminally misunderstood rock bands of all time. Cheerio!

Songbook: A Guide To Every Album By Progressive Rock Giants Jethro Tull, From This Was To The Zealot Gene