Velikovsky was a Russian-Jewish scientisit, psychiatrist and inter-disciplinary innovator. He was roundly hated by the cult of science, its tribal loyalties to itself and pseudo-science; and the media which demonized the Russian-Jew as a madman who dared to question the cult dogma of evolution, including slowly evolving algae becoming the strident Marxist-academic; and non-catastrophic uniformitarianism which is a central tenet of evolution and which implausibly believes that the earth's geological record is one of stability, calm, unending quietude, unburdened by catastrophe.

Velikovsky was pilloried because like Copernicus and Kepler, he challenged academic dogma and cant.

I have reviewed a few of his books:

Earth in Upheaval [review]

World's in Collision [review]

Mankind in Amnesia [review]

Not all that he wrote was 'correct'. I don't support his use of psychiatry and Freudian-quackery to explain why mankind has forgotten about the catastrophic events he lists, premised correctly as they are on cultural myths linked with what Velikovsky calls the hard facts of 'bones and stones'. However, even if a small percentage of what Velikovsky reveals is true, than modern science, geology, and cosmology will need a radical rethink.

In my view the ad-hominem attacks, devoid of real content, launched against Velikovsky by quackitists and quackademics, indicates that he was correct about many things. It reminds me of Copernicus who waited 20 years to publish his helio-centric view of the universe, not because he feared the church [he was a monk, funded by the church]; but because he was terrified of the academics who had invested their time, energy, money and prestige in the Ptolemaic universe. Little has changed in 500 years. [see here]