It has now been more than 40 years since the Recording Industry Association of America started handing out awards for million-selling LPs. Which makes this a good time to count down the biggest selling classic rock albums of all time.

The Eagles' compilation Their Greatest Hits (1971-1975) became the first album to be certified platinum back in February 1976. As you'll see in the gallery above, it's maintained a very high spot in this countdown. In fact, the classic rock genre pretty much dominates the RIAA's best-selling albums charts, with acts like Billy Joel, Led Zeppelin, Pink Floyd and AC/DC taking eight of the top 10 spots and 13 of the top 20 overall.

If you're dreaming of earning a place in this hallowed ground for yourself, our research quickly uncovered two simple "shortcuts" to long-term sales success. First, make a greatest hits album. Eight of the 25 best-selling rock albums on this list are best-of albums. Second, consider a double- or multi-disc album, because the RIAA counts each disc individually. That's a big part of how seven of these albums earned their place in line.

If you really want to stack the deck, put out a double-disc greatest hits album – Billy Joel and the Beatles both used this "double dip" method to get themselves high perches on this list. The tricky part is writing and recording enough great songs to warrant your own greatest hits album. But hey, we've done our part just by pointing you on the path to success, right?