Although it is one of her lesser known works, the early novella 'The Touchstone' is an excellent introduction to the style and themes of Wharton's later and more lengthy titles. It explores, among other things, the moral dangers that often go hand in hand with the exercise of free will. Moreover, as this is an early work, by beginning here and potentially moving on to later works, you will find yourself in an excellent position to chart the progress of the wonderful Wharton.