Dr. Immanuel Velikovsky, 84, the Russian-born author and scholar whose wildly unorthodox and widely published theories of cosmic evolution unleashed decades of scientific controversy, died of a heart ailment Saturday at his home Princeton, N.J.

At the time of his death, Dr. Velikovsky, who had been trained in medicine and had specialized in psychotherapy and psychoanalysis, had been continuing longstanding work on theories that combine science, the Bible, mythology and Freudian psychology.

In 1950, Dr. Velikovsky published the first of his iconoclastic works -- "Worlds in Collision." Based on his analysis and comparisons of the occurrence of catastrophe in the myth and legend of many ancient people, dr. Velikovsky in effect rewrote the history of the solar system.

Spurning the more conventional theories that described a gradual evolution of the earth and other planets, he wrote of heavenly bodies transformed by catacysmic occurences.

In 1500 B.C., he contended titanic forces ripped from the planet Jupiter a vast chunk of matter, some of which eventually smashed into our own planet, causing tidal waves, hurricanes, a halt in the rotation of the earth, and ultimately, some of the miraculous-seeming events described in the Bible.

In time, according to Velikovsky, the huge hunk torn from Jupiter settled into orbit around the sun, and became the planet Venus.

"Worlds in Collision" was followed by "Ages in Choas" (1952) and Earth in Upheaval" (1955).

Some observers praised Velikovsky for the breadth of his historical research and for the originality of his vision. At least one prominet journalist suggested that his work might bear comparison with Newton or Darwin.

Annoyed and outraged, however, several learned astronomers denounced Dr. Velikovsky as a charlatan, and his theories as worthless, and clear violations of the laws of physics. Dr. Harlow Shapel of the Harvard University Observatory spoke for many in the scientific community when he called the theories "rubbish and nonsense."

As the years passed, new evidence gathered by such techniques as deep space probes appeared to bear out some of Dr. Velikovsky's hypotheses and predictions.

Although some scientists maintained that he was the beneficiary of coincidence, and right for the wrong reasons, he was said to have accurately postulated such phenomena as the existence of radio emissions from Jupiter, of volcanic activity on the moon and the discovery that Venus is a hot planet.

Recognized as a spellbinding writer with a touch of the prophetic visionary, Dr. Velikovsky had also benefited in recent years by what appeared to be a decline in faith in conventional science, and a corresponding rise in interest in mystical, unconventional and supernatural explanations of unusual physical phenomena.

By 1974, "Worlds in Collision" alone had gone into its 72nd worldwide printing, and interviewers found Dr. velikovsky apparently unruffled by continuing opposition he faced. He looked forward to ulitmate vindication.

"I have been proven correct too many times," he told an interviewer.

"My old critics can no longer ignore my ideas and today's young scientists are open minded enough to listen to me."

The son of a Hebrew scholar and publisher, Dr. Velikovsky was born June 10, 1895, in the Russian town of Vitebsk, and moved in 1910 to Moscow where he obtained his medical degree in 1921.

Subsequently he studied in Berlin, practiced in what was then Palestine, and returned to Europe to work in psychonalysis and psychotherapy.

Preparation of a book on studies that Sigmund Freud had made of the acient world led Dr. Velikovsky to the same area of research and eventually to the theories set out in "Worlds in Collision."

Dr. Velikovsky came to the United States in 1939. He conducted the research on which his book was based at the Columbia University library in New York.

Survivors include his wife, Elisheva of the home, two daughters, Shulamit Kogan, of Israel, and ruth Sharon of Princeton, five grandchildren and two greatgrandchildren.