Mack Bolan had long entertained a bone feeling about San Francisco. His ground ear had been pulling him here ever since the nightmare in New York, the steady vibrations from that underculture of the national crime network telegraphing the insistent message that here was where the blood was at.

That certain feeling was intensified as the warwagon sped across the doubledecked engineering marvel known as the San Francisco-Oakland Bay Bridge and the fabulous skyline of that great old city came into view.

Down there was a population-density surpassed only in Manhattan, and a cosmopolitan atmosphere second to nowhere. It was more than a city; San Francisco was a way of life and a state of mind, an independence of the human spirit exuberantly expressed and often wildly exaggerated. There was the largest Chinatown outside the Orient, the most cohesive Italian community on the continent, and a general mixture of peoples and cultures more productive than any similar venture on the planet Earth.

It had started as the Spanish Presidio and Mission Dolores, in about the same year that the English colonies on the other American coast were proclaiming their independence. A scant fifteen years before the historic gold rush which put California on the continental map, the pueblo of Yerba Buena was established there, under the flag of Mexico, and in 1847 it was renamed San Francisco — a California Republic community of some eight hundred souls.

The discovery of gold at Sutler's Mill in 1848 produced a sprawling tent settlement of fortune hunters which was formally incorporated as the city and county of San Francisco in 1850. From this unlikely collection of miners, sailors, merchants, profiteers and prostitutes arose the queen city of the American West, cultural and financial center of the Pacific Coast, the grand old city beside the Golden Gate which now serves a metropolitan area of more than three million people, annually moving five billion tons of cargo through her seaport and fifteen million travelers through her airspace.

Most of the city's blueblooded families would prefer to forget the wild origins of the civic phenomena, once the port of entry for thousands of Chinese coolies who were imported as virtual slaves to mine the precious minerals and build the rail networks of the booming west; the bloody Barbary Coast where the iron men from wooden ships buried their months of ocean-going loneliness in a variety of pleasures. But hundreds of thousands of World War II servicemen would forever remember that same Barbary Coast with its roaring attractions of booze, broads, and brawls.

Less than a decade later, this same cultural spawning ground had become the womb of another original American creation, the Beat Generation — and the beatniks had hardly faded from view when a successive subculture, the hippies, appeared on the scene and established their unofficial headquarters in the big bawdy city at the Gate. And just across the bay, in Berkeley, the political revolution of American youth was born, to be spilled out and amplified in shock waves reaching throughout the nation.

And there was more to San Francisco. It was the city where the toughest cops in the world had been forced to barricade themselves inside their own police stations. It was the city where the most active hotbeds of Communism outside the Iron Curtains tensely coexisted with the western U.S. seat of Capitalism; the city where students wore crash helmets into classrooms; it was the western capital of homosexuality as well as the cradle of emancipated female eroticism — and it was still a city where a cabbie's first question was never "where to?" but always "wanta get laid, buddy?"

Yeah, Bolan knew San Francisco.

It was a city of natural beauty, sure — what was it the moviemakers called it? — the most photogenic city in the world? The fabulous hills and vertical streets and spectacular bay views were a cinematographer's dream come true. But there were "underground" views of equal interest to another rapidly emerging variety of moviemaker — San Francisco was also the porno movie capital of the country.

A city of interesting paradoxes, yes — and not the least of them was its newest ingredient: Mack Bolan.

Educated to kill and trained to survive the savageries of jungle combat, this American GI had returned from war to bury his own beloved dead — the victims of another sort of savagery at home — and to declare a war to the death upon "the greater enemy."

Bolan had earned fame in Southeast Asia as the Executioner. As a penetration team specialist and sniper, he had been officially credited with ninety-seven kills of enemy high-rankers, and he had been described by his commanding officer as "a self-propelled combat machine, and a formidable weapon of psychological warfare."

But in that same war zone, the young soldier was also known as "Sergeant Mercy" — the GI who could not turn away from orphaned kids and stricken villagers who were victims of the brutalities of warfare.

The homicide detective who investigated Bolan's initial "homefront battle" described the sergeant as "... an enigma. I don't know if I want to arrest the guy or pat him on the back. He's a killer, sure — but he's a killer with a difference."

That "difference" was the only thing that allowed Mack Bolan to tolerate himself and his new role in the world. He did not kill for personal gain, nor out of hatred or revenge. In his own view, he was simply a soldier doing his duty. His war was with the enemies of his society, enemies who had found protection from legal justice through a high degree of organization, political "clout" and financial power. By their own manipulations they had lifted themselves beyond the restrictions of the law.

In Bolan's understanding, they had also removed themselves from the protection of the law. Through their own actions and their own contempt for social justice, they had thrown themselves into the court of jungle law — and here were no judges, no juries — here was simply life and death, the survival of those fittest to survive, and here Mack Bolan was the Executioner. So long as he lived, those others would die. This was Bolan's "difference." He was in a state of war — with those who were unfit for survival.

His jungle knew no geographical boundaries. It existed only in the hearts and actions of certain men, in the territorial environs of a criminal conspiracy known variously as the Mafia, La Cosa Nostra, the organization, the syndicate — or, collectively, the mob.

And, yes, in that exciting old city beside the Golden Gate, in that paradoxical town of human extremes, there existed a jungle of considerable dimensions.

And Death moved coolly upon the scene, and sniffed the air, and bent an ear to the ground, and knew that the time was right for the California hit.

The Executioner was on the scene.

And the golden city knew immediately that she had a hot war on her hands.