The fact that "Changes" is the first song on Hunky Dory (1971) is a useful crutch for an unimaginative writer. So here goes: the album represents a remarkable change from The Man Who Sold The World, with the Hard-Rock/Proto-Metal of the latter replaced by the 1970s pop sound of folk-memory. This is the Bowie that starts playing in your head when someone says "David Bowie". This is an album which contains not only "Changes", but also "Life On Mars" and "Oh! You Pretty Things", demonstrating that this is the start of Bowie's most fertile period.
One of the interesting things about reading someone else's opinions on music is that you're suddenly confronted with things you've been mishearing for years. I'm pretty sure that I'm not the only one who thought it was "Turn to face the strain" rather than "Turn to face the strange" on "Changes", although I was perhaps alone in hearing "Now the workers have struck for vain/'cos Lenin's on sale again" rather than "Now the workers have struck for fame/'cos Lennon's on sale again" in "Life on Mars".
While the album represents a change of direction musically, the lyrical themes are very consistent with The Man Who Sold The World: transcending the limits of humanity, occultism (The Nietzschian "Homo Superior" of "Oh! You Pretty Things" is supplemented by a casual reference to Himmler on "Quickand", an early indication as to where the darker part of Bowie's psyche will be heading in a few years), and insanity. This is also an album about fame, and Bowie chooses to wear his influences on his sleeve, with songs explicitly about Andy Warhol and Bob Dylan, and "Queen Bitch" commonly reckoned to be about Lou Reed (although Doggett's book makes a persuasive case for it being a jealous swipe at Marc Bolan's new-found stardom).
So here's the mystery: it's a really good album, with some excellent songs, so why wasn't it a massive success? The single of "Changes" failed to make the Top 40, which is so improbable it makes your head spin. The answer may be the lack of a central strand: all the elements of Bowie's success are here, but there's a lack of a central something to make the diverse elements come together cohesively.
But something is coming...