The CISG contains no provisions that a contract for the sale of goods be supported by consideration. Further, the CISG does not address questions related to the validity of the contract, such as legality, mistake, fraud, duress, or undue influence. How will national courts handle these issues in cases that they might be called upon to decide under the CISG? In common law countries? In civil law countries of Europe? How has this been addressed by courts in the United States?