I could answer "defining album of the 80s" in a couple of ways. If I think in terms of albums that culminate the trends of the past with excellence, I could argue for Michael Jackson's "Thriller" or Bruce Springsteen's "Born in the USA."

But if I think in terms of an album that defined the future of music, there is only on answer, and that answer is U2's "The Joshua Tree." It was a critical and commercial blockbuster, but more importantly, every aspect of it has proven incalculably influential in the thirty years since it was published. Vocalists everywhere have tried to imitate Bono's singing. Guitar players everywhere have picked up The Edge's jagged, echoing single note melodic lines to replace the power chords of hard rock. Rhythm sections everywhere have adopted Mullen and Clayton's steady eighth note techniques. In Britain, the most popular bands (e.g. Coldplay) and the most critically acclaimed bands (e.g. Radiohead) are unthinkable without U2.