A proud member of the mint family, Basil has that characteristic square-shaped stem with a touch of fuzz. The aroma of fresh basil is reminiscent of mint, but with a hint of spicy clove. White or pinkish-purpley flowers appear as a whorl in summertime. I've heard it said that the leaves are best for culinary use if the flowerheads are kept at bay by pinching. In fact, this herb does really well if you pinch off the top pair of leaves on a stem - it will grow back twice as nice!
Classic culinary applications include pesto, all things Italian, and Thai (use Thai basil). This plant grows well with tomatoes, and it is said they will improve each other's flavours.
Be sure to curse at and vilify this herb as you plant it, as legend has it basil thrives when verbally abused! The French idiom "semer le basilic," "to sow the basil," in reference to ranting, comes from this idea.