Experiments on authorship attribution by intertextual distance in English

How can it be said that texts are "near" or "distant" from one another? Are different texts by a single author more similar than texts by different authors? To answer these questions, a method is proposed by combination of the calculus of intertextual distance with automatic clustering and tree-classification. A blind test and some additional experiments show that this method offers an interesting tool for non-traditional authorship attribution.