This guide explains how to handle civil subpoenas under Federal Rule of Civil Procedure 45 from three perspectives: the party who issues one, the opposing party watching subpoenas hit its business partners, and the nonparty who gets served. For a subpoenaed nonparty, the cheapest first move is usually a written objection under Rule 45(d)(2)(B), which shifts the burden onto the issuing party, rather than an immediate motion to quash, and the 14-day objection deadline is an easy trap to miss. Issuing parties face real limits, including the advance-notice requirement of Rule 45(a)(4), proportionality under Rule 26(b)(1), and mandatory cost-shifting when a compelled nonparty incurs significant expense. An opposing party usually cannot quash a subpoena served on someone else, because it lacks standing absent a personal right or privilege, so its workhorse tool is a Rule 26(c) motion for a protective order filed in the court where the case is pending. The most effective attack on investor and business-partner subpoenas is often a coordinated one, with aligned nonparties objecting on burden and cost while the party moves to limit scope and challenge improper purpose. Throughout, the piece stresses that meeting and conferring, narrowing requests, and papering a protective order beat motion practice, and it uses trademark litigation as the running example because those cases scatter relevant records across manufacturers, retailers, and investors.