Brooks was writing well ahead of his time, and his super-scientific druidic magic actually predicted cell phones, wireless ethernet, and the concept of the prepaid phone card (metaphorically represented through the elfstones, which appear to be mere trinkets but contain ultimate power provided that the user possesses the self-knowledge, or personal identification number, necessary to unlock the power imbued into it in the form of minutes).
Lord of the Token Ring: An Examination of Druidic Magic as a Naturalistic Interpretation of Superscience in Hard Science Fiction