THIS IS PARTLY DUE TO THE FACT THAT PRISONS NEVER CAUGHT UP WITH THE RISE OF PRISON POPULATIONS BY MORE THAN 10 PERCENT A YEAR IN THE MID-1970'S. MOREOVER, CORRECTIONS OFFICIALS FEAR THAT A NEW ROUND OF GROWTH MAY BEGIN AGAIN, FUELED BY THE FLAT SENTENCING LAWS AND SENTENCING GUIDELINES ADOPTED BY STATE LEGISLATURES IN RECENT YEARS. OVERCROWDING, WHICH WAS ONCE A MAJOR CONCERN IN THE SOUTHEAST, IS NOW A PROBLEM OF LARGE STATES IN ALL PARTS OF THE COUNTRY. IN CALIFORNIA, THOUSANDS OF PRISONERS ARE DOUBLED UP IN CELLS; TEXAS HAS MORE PRISONERS NOW THAN THE U.S. BUREAU OF PRISONS; AND OVERCROWDING CAUSES TENSION IN PRISONS IN NEW YORK AND ILLINOIS. THE NUMBER OF PRISONERS HELD IN STATE SYSTEMS (275,850) INCREASED AT ABOUT THE SAME RATE LAST YEAR AS THE YEAR BEFORE, BUT THIS WAS OFFSET BY A 16-PERCENT DROP IN THE NUMBER OF PRISONERS IN THE FEDERAL SYSTEM. FEDERAL OFFICIALS ATTRIBUTE MUCH OF THIS DECREASE TO A SHIFT IN EMPHASIS ON PROSECUTION FROM STREET CRIME TO WHITE-COLLAR CRIME. PRISON POPULATIONS DECLINED IN 19 STATES DURING 1979, BUT AMONG THE 11 STATE SYSTEMS WITH MORE THAN 10,000 INMATES, ONLY FLORIDA REGISTERED A DECLINE. BESIDES NEW SENTENCING LAWS AND PAROLE GUIDELINES, OTHER FACTORS HAVE AFFECTED PRISON POPULATIONS, SUCH AS A GENERAL ECONOMIC SLOWDOWN, POPULATION SHIFTS, AND A MORE PUNITIVE ATTITUDE THROUGHOUT THE COUNTRY AMONG JUDGES, PAROLE BOARDS, AND LEGISLATORS. A CHART AND PHOTOGRAPHS COMPLEMENT THE TEXT.