Engrossed in a book
Translation of "engrossed in a book" into Russian
engrossed in a book
погружённый в книгу
He was completely engrossed in a book and didn't notice the time passing.
Он был полностью погружён в книгу и не заметил, как прошло время.
Definitions
Completely absorbed or deeply focused on reading a book, to the extent that one is unaware of their surroundings.