Federal Circuit Makes a Leap in Logic: The Dangerous Upstream Use of Related Patents' Prosecution History to Interpret Claims in Already Issued Patents, The

The Federal Circuit, in Microsoft Corp. v. Multi-Tech Systems, Inc., used prosecution history from a subsequent related patent application to limit claim language in an earlier patent and settle an important legal battle affecting the rapidly growing internet telephony industry. This Note examines the majority’s seemingly logical reasoning but ultimately agrees with the analysis of Judge Rader’s dissent.