Preheat the oven to 500°F.
Remove the beef from the refrigerator about half an hour before you want to cook it, to bring it to room temperature.
Place it in a roasting pan.
In a small bowl, stir the olive oil and garlic into a paste.
Season with salt and pepper.
Coat the tenderloin with the garlic paste, rubbing it in well with your hands.
Roast for 15 minutes, or until browned.
Lower the heat to 375°F, and cook for another 20 minutes, or until it reaches your desired level of doneness. Use a meat thermometer to be sure (internal temperature of 145°F for medium-rare and 160°F for medium).
Rest the beef for 10 to 15 minutes before slicing thinly and serving on a bed of arugula.