Ah, to be in the mood for oud. This luxurious perfume resin comes from the heartwood of agar trees. If you happen to unroll the Torah sometime soon and see a reference to a variety of long-lasting incense called "aloes," it's thought that oud is what they're talking about. The scent is instantly identifiable once you've experienced it, but it can be compared to other rich, pungent incenses like myrrh. Oud is still very commonly used as an incense and perfume in Japan and throughout the Middle East, particularly in Saudi Arabia, and it's experiencing a surge in popularity here in the US as well. Look for it in high-end fragrances from the Oriental genre, like Le Labo's Oud 27 ($200), or Trish McEvoy Precious Oud ($100). It's not cheap, but it's definitely worth a sniff.