Travel agents require a copy of your passport primarily to ensure absolute accuracy in booking your international travel. Airlines, cruise lines, and border authorities are extremely strict regarding names; even a single-letter typo or the omission of a middle name as it appears on the document can result in a traveler being denied boarding or facing expensive name-change fees. Having a copy allow the agent to verify the exact spelling, the passport number, and the expiration date, which must typically be at least six months beyond your return date for many countries. Additionally, agents often need this information to secure visas, process mandatory "Advance Passenger Information" (API) for government security agencies, and assist you in the event of an emergency where your physical passport is lost or stolen. By keeping a secure copy on file, they act as a safeguard against administrative errors that could otherwise jeopardize your entire vacation or business trip before it even begins.