Handwriting is the act of writing with a writing instrument in one's hand, such as a pen or pencil. Handwriting is distinct from formal calligraphy or typeface and includes both printing and cursive styles. Because each person's handwriting is unique and different, it can be used to verify the authorship of a document.  Handwriting deterioration can also be a symptom or result of a variety of diseases. Dygraphia is the inability to produce clear and coherent handwriting.