From Wikipedia... <a href="http://en.wikipedia.org/wiki/Contract">http://en.wikipedia.org/wiki/Contract</a> [wikipedia.org] If the terms of the contract are uncertain or incomplete, the parties cannot have reached an agreement in the eyes of the law.[19] An agreement to agree does not constitute a contract, and an inability to agree on key issues, which may include such things as price or safety, may cause the entire contract to fail.