He is an expert in psychiatry.

He is known as an expert in population genetics.

He is an expert in theoretical physics.

He is an expert in phytopathology, making a significant contribution to agriculture.

He is an expert in ethology, and his research is highly regarded worldwide.

He is an expert in algebraic geometry.

He is an expert in topology.

I am very interested in sociolinguistics.

He is majoring in oenology.

He has a deep interest in parapsychology.