If you don't know who Def Leppard is or have never heard of the album Pyromania then you are probably not an 80s child and if you were then you lived under a rock. This album is the genesis for Dep Leppard. There were albums before this one but this album really got people to notice who the band was and what they were capable of. Anyone who is a die hard DL fan will tell you that this album is significant because most everyone agrees that every song is a hit. This phenomenon is rare and Tesla's Mechanical Resonance is the only album that I know of who's fans will say the same of. Don't waste your time or money on any other album if you aren't sure if you like DL. Any greatest hits album (i.e. "Vault") will contain about 75% of the songs from this album and leave you missing out of the other outstanding 25%. Just get it, you know you wanna.