Dr Tewari's main contributions have been in the area of Harmonic Analysis. He has been particularly concerned with Segal Algebras. His work proving the existence of Segal Algebras on non-compact locally compact abelian groups, with multiplier algebras different from the measure algebra, is essentially a significant contribution to this field. His extension of F and M Riesz Theorems to operators on certain Segal Algebras is another important contribution. His work on the multiplier algebra as well as the algebra of translation invariant operators on the group algebra of vector valued function is also of considerable importance.