Rajesh Kumar is an extremely prolific Tamil novel writer, most famous for his crime, detective, and science fiction stories. Since publishing his first short story "Seventh Test Tube" in Kalkandu magazine in 1968, he has written over 1,500 short novels and over 2,000 short stories.

Many of his detective novels feature the recurring characters Vivek and Rubella. He continues to publish at least five novels every month, in the pocket magazines Best Novel, Everest Novel, Great Novel, Crime Novel, and Dhigil Novel, besides short stories published in weekly magazines like Kumudam and Ananda Vikatan. His writing is widely popular in the Indian state of Tamil Nadu and in Sri Lanka.