Certainly, 1973's Ziggy Stardust And The Spiders From Mars had its moments, but it stayed too close to its theme and, frankly, had some dull patches. Aladdin Sane, however, ratchets up everything good about Ziggy, abandoning a theme in favor of a real rock record, with some of Mick Ronson and Bowie's best guitar work to date. 
Bowie and company charge out of the gate with the rollicking "Watch that Man" before settling into the psychedlic title track, which hearkens back to Bowie's beginnings and relative obscurity (this was his fifth album). The best part of this song is not the solid drum/bass interplay, the spacy vocals, or the wispy electric guitar; it's the random, all-over-the-place piano solo in the middle of the song that has no point but works beautifully because of its spontaneity.
"Drive-in Saturday" and "The Prettiest Star" seem like the same song; fans love this, but they are doo-wop yawners without real hooks. "Panic in Detroit" is redeems these two, a kinetic Iggy Pop-type tune that uses descending riffs in the verse/chorus and apocalyptic lyrics to tell the story - coming after the riots in the 60s, it's somewhat timely as well.
Ronson then turns up the guitar crunch on "Cracked Actor," certainly the loudest and hardest song of Bowie's canon and this album's best. The lyrics discuss the rise and fall of Hollywood egos -- paralells to Ziggy Stardust, maybe? -- amidst a head-bopping hard-rock backdrop. This is followed by the Tom Waits-like "Time" and a cover of "Let's Spend the Night Together;" the former's chorus is catchy but takes time to burrow into your head, while the latter is just average. Finally, Bowie closes with "Jean Genie," which is incredibly catchy and features better drumming than one may remember, and the ballad "Lady Grinning Soul," which ends the album on a needless sad note.
As with most of Bowie's work and life, this album is a bit too scattershot to be a classic rock masterpiece, but at least half of it is must-own for both Bowie and rock fans. Bowie would go on to explore more visions, collaborate with Brian Eno, record several pop hits and settle into middle age gracefully, but he never again achieved the pure fun and glam rock heights of this disc.