With Philip Glass's 75th birthday mere hours away, the music world is abuzz with various productions and concerts.

And as the composer, who was a 2010 NEA Opera Honoree, prepares for premieres and notable returns—including a world tour of Einstein on the Beach that counts BAM as one of its stopovers this fall and a recent revival of Satyagraha at the Met—now's as good a time as any to examine the composer's myriad operas, many of which have made it to recording.

But for the Glass neophyte, where to start is always a tricky thing. We at Operavore have made the process a bit easier, siphoning Glass's pieces down to their meaty thematic roots. Start with the basic question at the top and work your way down our fail-proof flowchart (too small? Right click and select "View Image" to see it in its full-sized glory).