Negotiable instruments include promissory notes, bills of exchange, and cheques. These are documents used in commercial transactions to transfer money from one party to another. A negotiable instrument must be in writing, signed by the maker, contain an unconditional promise to pay a certain sum to a specific person or entity, and be payable on demand or on a specific date. The key parties involved are the maker, drawer, drawee, acceptor, payee, and holder. For an instrument to be negotiated, it must be delivered to a new holder by endorsement and delivery.