The formal study of handwriting began in Europe, with early writers cataloguing how personality seemed to show up in strokes. Jean-Hippolyte Michon coined the term graphology in the 1870s.
Later, teachers in the United States built a more practical, trait-based system, focused on measurable features you can point to on the page.
Modern practice keeps the useful parts, stays honest about the limits, and treats handwriting as one lens among many rather than the whole picture.