The central theme of this novel is indicated through the principal characters of Waldo and Arthur. Although they seem locked together in constant conflict, what is key to realise abotut them is that they are used to symbolically represent the two opposing halves that make up the self that lies with all of us. White seems to be arguing that we all need both parts within us, but kept in some kind of balance. Ideas of wholeness and twinhood, together with issues such as communication and profound links between humans is therefore something that is a significant part of this novel.
Another theme that you could comment upon is that of sexuality and how human sexuality is expressed through these characters. Both Arthur and Waldo propose to Dulcie in this book, but their motives are hardly based on pure love or even lust. Waldo proposes because he thinks this is what society calls him to do, and Arthur proposes because he is more in love with Dulcie's innocence than with Dulcie herself. Both men are presented as being more asexual, or as having characteristics that are neither male or female. For example, Waldo wears one of his mother's old dresses at one stage. White suggests in this novel that every self is actually made up of elements of both genders, and that if we allow one to gain control over the other this can actually be unhealthy for us.
he title of this work refers to the special kind of marble that Arthur prizes so highly. Four of his marble collection are solid mandalas. The symbolic significance of the mandala relates to the idea of totality and wholeness. In addition, it is supposedly a dwelling place for a god. Geometrically, a mandala is represented by a square placed inside a circle, representing order imposed on chaos. Remember that this work above all else focuses on two twins moving towards wholeness. Given this dominant theme, the concept of the mandala as both a symbol of totality but also of imposing order on the chaos of Arthur and Waldo and their relationship. The title of this novel therefore points towards its central themes and how they impact its two central characters.