He is an expert in bibliography and has many publications.

He is an expert in sociology.

Taxonomy is the science of finding, understanding, and naming species of organisms.

Phonetics is a part of linguistics that studies the physical, physiological, and psychological aspects of sounds.

He is an expert in entomology, especially knowledgeable about butterflies.

Cytology is a branch of biology that studies the structure and function of cells.

He is majoring in economics.

He is an expert in bacteriology.

In geology, morphology is the field that studies the shape and structure of the terrain.

Geomorphology is the science that studies the surface shape of the earth.