Most bonds are straightforward: you get regular coupons and your money back at maturity. But some bonds come with extra features—like a “call” that lets the issuer pay early, or a “put” that lets the investor demand early repayment—which reshape the bond’s risk and return. And just as you can insure a car, you can insure a bond against default using a credit derivative called a credit default swap. In this chapter we’ll explore both: bonds with secret options hidden inside them, and the clever tools that let investors trade and transfer credit risk.