He is known as a government scholar.

He is a famous psychologist, influencing many people.

He is a world-renowned geologist.

He is a world-renowned osteologist.

He is a renowned anthropologist, traveling around the world to study human cultures.

He is a renowned political scientist who has written many important papers.

He is a world-famous geographer.

He is a world-famous physicist.

My father is an ichthyologist and has a deep knowledge about marine life.

He always likes to be pedantic, explaining things down to the smallest detail.