The invention relates to (hetero)aryl cyclopropylamine compounds, including particularly the compounds of formula (I) as described and defined herein, and their use in therapy, including, e.g., in the treatment or prevention of cancer, a neurological disease or condition, or a viral infection. Thus, in one specific aspect the invention relates to formulas (II), (III), (IV), (V), (VI), (VII), (VIII), (IX).