 Some of his books covered areas of Christian apologetics such as "Prathiyukthi", and "Satyaprakashini" and "Krushil Maricha Kristhu (Christ who died on the Cross)", — which were compiled from notes prepared from his rebuttals to anti-Christian critics.He also wrote "Satyaprakashini", an apologetics book attempting to refute Hindu critics by quoting from Hindu scriptures.Simon also spoke out against Russian traveller Nicolas Notovitch's controversial claims that Jesus had visited India between the ages of twelve and thirty, studying under Hindu, Buddhist, and Jain teachers.