Over a career spanning years, UFO have released 22 studio albums, 14 live recordings, 16 compilation albums and one album of cover songs. They achieved moderate success in the late 1970s and early 1980s with several albums and singles (including their 1979 live album "Strangers in the Night") in the UK and US Top 40 charts, and have sold over 20 million records worldwide. Some of their best-known songs include "Doctor Doctor", "Rock Bottom", "Natural Thing", "Lights Out", "Too Hot to Handle" and "Only You Can Rock Me". UFO are considered one of the greatest classic hard rock acts, and often cited as one of the key influences on the 1980s and 1990s hard rock and heavy metal scenes. The band were ranked number 84 on VH1's "100 Greatest Artists of Hard Rock".