inside baseball

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 This has come to mean esoteric knowledge known only to experts in the field.

I want you to give me the inside baseball on the housing market. It is an American expression just making its appearance in our variety of English, and it does come from baseball where it referred to the kind of technical talk that experts and aficionados would indulge in, leaving ordinary people somewhat bewildered.  Given the significance of baseball to the Americans, it is understandable that baseball jargon and expressions make their way into other spheres of life.