Guest editor Katia Beauchamp knows a lot more about beauty than your average Harvard Business School grad and entrepreneur. After all, she's the founder of Birchbox -- you know, that company that sends the cute little box full of amazing product samples every month. It's kind of like a department store beauty counter delivered straight to your mailbox.

After three years at the helm of Birchbox, it's safe to say Katia knows her stuff when it comes to beauty. Taking full advantage of her guest editorship, we asked Katia to share her favorite products -- the ones she's discovered along the way and just can't live without. From her favorite mascara to the ultimate nude nail polish, we've got the scoop right here.

Click through the gallery to see Katia's beauty essentials!