  Traditional clustering identifies groups of objects that share certain
qualities. Tangles do the converse: they identify groups of qualities that
often occur together. They can thereby discover, relate, and structure types:
of behaviour, political views, texts, or viruses.
  If desired, tangles can also be used as a new method for traditional
clustering. They offer a precise, quantitative paradigm suited particularly to
fuzzy clusters, since they do not require any assignment of objects to the
clusters which these collectively form.
  This is the first of four parts of a book with the above title. The book
explores applications outside mathematics of the notion and theory of tangles
generalised from the graph tangles know from graph minor theory.
