This painting is very valuable.

In Marxism, surplus value refers to the part of the value produced by workers, excluding the part necessary to maintain their own livelihood.

He has expert knowledge.

He is studying computer science at a specialized school.

He couldn't say anything about issues outside of his field of expertise.

Could you bring my notebook?

There are many different specialty stores in this town.

He brought me an old map.

He showed me his new toy.

He is a specialist fool, with no interest in anything outside his field.