A chemical engineer has developed a new chemical formularfor a fuel additive. He has written a textbook containing the formula. He has also started a new company to market his fuel additive, and has decided to use his initials as the company logo. He decides to have a colleague assist in writing the textbook. The agreement is such that the colleague will spend 10 hours per week helping write the book, but no payment will be made for the work. After several months, the colleague has not contributed any material for the book, so the engineer decides to file a lawsuit for breach of contract. Is the lawsuit valid? If no, on what basis is the contract invalid.