- know\ smth\ inside\ out
- v. phr.To be extremely well conversant with something; be an expert in; have thorough knowledge of.
Tom knows the stock market inside out.
Словарь американских идиом. — СПб., Изд-во "Лань". Оригинал: A.Маккей, М.Т.Боткер, Дж.И.Гейтс. 1997.