The document discusses negotiable instruments under the Negotiable Instruments Act of 1881. It defines key terms like cheque, promissory note, bill of exchange. It describes the characteristics of negotiable instruments like being transferable and signed documents. It then explains the different types of cheque crossing - general, special, restrictive, non-negotiable. It also discusses endorsement types like blank, special, restrictive, partial and conditional. Finally, it defines material alteration and what would constitute a material change to a negotiable instrument.