THE PAST DECADE OF FOURTH AMENDMENT LITIGATION AND COMMENT PRODUCED NUMEROUS ATTEMPTS TO PROPERLY INTERPRET THE SUPREME COURT'S LANDMARK DECISION IN KATZ V. UNITED STATES, 389 U.S. 347 (1967). KATZ REPRESENTS A MODIFICATION AND EXTENSION OF THE TRADITIONAL FOURTH AMENDMENT ANALYSIS WHICH FOCUSED ON THE ABSENCE OF PHYSICAL INVASION INTO A CONSTITUTIONALLY PROTECTED AREA. IN APPLYING KATZ, THE LOWER COURTS HAVE GENERALLY ADOPTED A 'REASONABLE EXPECTATION OF PRIVACY' TEST TAKEN FROM JUSTICE HARLAN'S CONCURRING OPINION. LOWER COURT DISCORD AND NUMEROUS SUPREME COURT REVERSALS REVEAL, HOWEVER, THAT A SETTLED AND WELL-DEFINED APPROACH TO FOURTH AMENDMENT ISSUES HAS YET TO EMERGE. CONFUSION HAS BEEN ATTRIBUTED TO THE LACK OF OBJECTIVE CRITERIA AVAILABLE IN APPLICATION OF THE 'REASONABLENESS' TEST TO SPECIFIC FACTUAL CIRCUMSTANCES AND TO CONTINUED RELIANCE ON TRADITIONAL CONCEPTS. SINCE 1967, A NUMBER OF APPELLATE COURTS HAVE CONSIDERED WHETHER THE WARRANTLESS USE OF BINOCULARS OR OTHER TELESCOPIC VISUAL AIDS TO PEER INTO PRIVATE PREMISES VIOLATES THE FOURTH AMENDMENT. THE MOST RECENT OF THESE DECISIONS, UNITED STATES V. KIM, 415 F. SUPP. 1252 (D. HAWAII 1976), WAS THE FIRST TO EXCLUDE EVIDENCE BECAUSE IT WAS OBTAINED THROUGH THE WARRANTLESS USE OF SUCH AIDS. HOWEVER, PROOF THAT THE ISSUE REMAINS CLOUDED MAY BE FOUND IN COMMONWEALTH V. HERNLEY, 216 PA. SUPER. CT. 1977, 263 A 2D 904 (1970), IN WHICH EVIDENCE DERIVED THROUGH BINOCULAR SURVEILLANCE WAS ADMITTED. THE MOST SIGNIFICANT ASPECT OF THE KIM DECISION IS ITS RECOGNITION OF THE NEED FOR FOURTH AMENDMENT PROTECTION COVERING THE INCREASING TECHNOLOGICAL CAPABILITY OF LAW ENFORCEMENT AGENCIES. FOOTNOTES ARE PROVIDED. (LWM)