National Catholic Register, Joseph Pearce:
One of the most powerful lessons that Tolkien teaches in The Hobbit and The Lord of the Rings is that the things possessed can possess the possessor. This addictive possessiveness, or what might be called crass materialism, is known as the “dragon sickness” in The Hobbit. It afflicts not only the dragon Smaug but several other characters. In The Lord of the Rings this dragon sickness manifests itself in the power of the Ring, in which those who covet the Ring’s power become subject to the very power they hope to obtain, possessed by their possessiveness so that they become possessed by their possession of it. This lesson is a reiteration of the lesson that Christ teaches that where our treasure is, there our heart will be also. It is, therefore, important that we learn to desire those treasures which are truly good for our souls, and not those which will imperil them. Continue reading here.