Invalidity of legal transaction, made by a person incapable neither to realize the implication of his actions nor to be in control of them

The article concerns an issue of a transaction validation in default of both will and its declaration, including transactions made by a person incapable neither to realize the implication of his actions nor to be in control of them. The author points out the difficulty in establishing the factual state of such a person, denotes natural persons and legal entities eligible to impeach this kind of transactions, and gives an example from the law enforcement practice.