In the following contribution, transplant theories are tested, this time through the example of commercial law comparisons. The piece belongs with the papers on the theory of transplants, and therefore, the theory of comparative law, and also commercial law. The worldwide movement towards harmonization of commercial law makes it pertinent to question how legal transplants can or will function in this field. Commercial law transplants are 'extremely common', and 'many hopes are pinned on them'; but can transplant theories be used to predict whether these transplants will work? This contribution analyses the current debate on legal transplants by dividing modern literature into 'culturalist' and 'transferist', and considers the recent attempts to move on from this debate. In this, it looks at the works of Watson, Legrand, Seidman, Kahn-Freund, Ewald and Teubner, as do many of the other contributions. Foster, however, tests these approaches in the field of commercial law, specifically as related to universal security in England, France and Quebec, to find out whether commercial law is 'closely linked' to social processes or divorced from culture. In doing this, he looks at the English 'floating charge' and the opposite positions in England and France, which he then analyses in the example of Quebec, 'an island of civilian law in a sea of common law'. In looking at the French example the conclusion is, that the culturalists are right, but when looking at Quebec, that the transferists are right. Does the 'social processes' idea provide a better answer? In order to refine the search, Foster looks at commercial law and culture. We are led into mental gymnastics, by considering various possibilities, to show, for example, that probably one of the theories of legal transplant may be correct but that we have insufficient information to prove that. Are we leaving out from our equation one of the dimensions of analysis: culture, society, economy, history, politics or legal logic? If there are misunderstandings surrounding Watson's legal transplant theory, is it possible to consider Ewald and Teubner as corrections, or, is there something wrong in the methods used? As far as commercial lawyers are concerned, we arc told that they, want an answer to the question, 'How, will this transplanted law work?" Can there be predictions." If not, can transplant theory he a theory at all, or, is it really just a hypothesis? Foster contends that transplants vary so much that broad generalizations cannot be offered and therefore there cannot be a Grand Transplant Theory. The conclusion may have to be that, not only is there no one thing called a 'legal transplant', but neither is there only one meaning attached to the word 'work' in the question, 'do legal transplants work?' The reader may be interested in comparing the concept 'work' used by Foster, with the concept 'succesful' used by Smits and Nelken, and rethink the whole field of transplants and metaphors after reading this chapter. We can only be aware of the complexity and try to reformulate our research questions. Foster suggests a move from simplicity to complexity, admits that no predictive answers can he given to commercial lawyers, and demonstrates amply that the comparative law venture seeking explanations for 'the true Junction of comparative law, is full of pitfalls. The problems will only act more intense with globalization.