idiom-requests
I was wondering if there's an idiom or expression for a person who knows everything there is to know about his field of interest or expertise, practically no detail is unknown to them.
I thought of the expression: knowing like the back of hand, but I guess that has a geographical sense to it and is used for cities, streets and neighbourhoods. (Please correct me if I'm mistaken.)
I hope I was clear. Thanks in advance.
Since he developed this software framework himself, he knows the ____ and ____ of it.
Since he developed this software framework himself, he knows the ins and outs of it.
Thanks, Cpt. Obvious!
Loosely related to the expounder Mr. Exposition, a TV trope that provides infodumps or expounds the plot. An agitator or lamentor.
Additionally, AYKB (As you know, Bob), discussed here (Info dumps, Soap-boxing, Lecturing).
Sometimes described as the Turkey City Lexicon, or a FAQ Literator.
Loosely related concepts are: perverbs or Wellerisms (making fun of established clichés and proverbs by showing that they are wrong in certain situations, often when taken literally) and Tom Swifties (a speaker attribution that puns on the quoted statement).
Best Answer
In this situation, I would say he "knows it backwards". The implication is that one knows something so thoroughly that they could do it in reverse.
Also consider
"knows it backwards and forwards"
{Cambridge Dictionary of American Idioms}
and "knows it inside out"
{McGraw-Hill Dictionary of American Idioms and Phrasal Verbs}.
"knows it like the back of his hand" does often, but not always, have a geographical connotation.