THE BOOK RESULTS FROM A 2-YEAR STUDY OF OVER 150 MUNICIPAL AND COUNTY POLICE DEPARTMENTS WHICH HAVE 150 OR MORE FULL-TIME EMPLOYEES OR WHICH SERVE JURISDICTIONS WITH POPULATIONS OF OVER 100,000. THE DOCUMENT BEGINS WITH A DISCUSSION OF VARIOUS ACTIVITIES WHICH MAKE UP THE INVESTIGATIVE FUNCTION, AND METHODS BY WHICH SUCH ACTIVITIES MIGHT BE EVALUATED ARE PRESENTED. ALSO INCLUDED IS A DESCRIPTION OF THE WAY INVESTIGATIONS ARE TYPICALLY CONDUCTED, ALONG WITH A DESCRIPTION OF THE CHARACTERISTICS OF INVESTIGATORS, THE PROCEDURES THEY FOLLOW, AND THEIR RELATIONSHIPS TO OTHER POLICE ACTIVITIES. VARIOUS APPROACHES TO MEASURING INVESTIGATION EFFECTIVENESS ARE DELINEATED. ANOTHER SECTION REPORTS ON THE RESPONSES TO THE QUESTIONNAIRE SURVEY AND INCLUDES THE FOLLOWING: A DESCRIPTION OF THE DESIGN AND ADMINISTRATION OF THE SURVEY QUESTIONNAIRE; RESULTS OF THE SURVEY; AND A DESCRIPTION OF THE DIFFERENCES AMONG DEPARTMENTS WITH REGARD TO POLICIES, AND RESOURCES USED. OPERATIONAL CHARACTERISTICS ARE IDENTIFIED AND THEN RELATED TO STANDARD GROSS PERFORMANCE MEASURES SUCH AS CLEARANCE AND ARREST RATES. THE THIRD SECTION PRESENTS A COMPREHENSIVE DESCRIPTION OF THE CRIMINAL INVESTIGATION PROCESS AND AN ANALYSIS OF THOSE ISSUES THAT CAN BE ILLUMINATED BY QUANTITATIVE EVIDENCE. THE FINAL PART OF THE BOOK IS A SYNTHESIS OF THE OVERALL FINDINGS OF THE STUDY, AND PRESENTS CONCLUSIONS AND RECOMMENDATIONS. A BIBLIOGRAPHY IS ALSO PROVIDED. (AUTHOR ABSTRACT)...KAP