In general, the act makes illegal the delivery of specified substances without the authorization of a registered practitioner. Its definition of 'delivery' criminalizes three types of behavior: actual transfer, constructive transfer, and the offer to sell. Constructive transfer is a legal term that has no meaning in common usage or Texas law. The Texas Court of Criminal Appeals has examined constructive transfer on several occasions, but has declined to define the term and implied that constructive transfer encompasses a potentially infinite number of situations. In addition, no definition of constructive transfer can be found in the case law of Texas' intermediary appellate courts. A review of the constructive transfer cases shows that in each case a Texas prosecutor could have pursued the delivery conviction on an actual transfer theory. Constructive transfer, however, does provide the State with a catchall theory of liability in complicity cases. This deprives the defendant of the protection of other theories that require the jury to make specific findings to ascertain guilt. Two factors should be considered in analyzing a statute under the void-for-vagueness doctrine: does the law give fair notice of proscribed conduct, and does it provide sufficient guidance for enforcement? Constructive transfer fails on both issues and therefore is unconstitutionally vague. The paper contains 110 footnotes.