Knowledge5

teacher speaking, student hearing
then scribbling on thaala pathra
papyrus / paper, printing m/c and books
book and teacher
audio video
distant education
internet , e books, on line library, self help without teacher
things are evolving leaving behind book and teacher of old type
innernet ,  inner field of knowledge, gaining access to it, the source of knowledge within, unlimited expansion of it are new possibilities. every new discovery makes earlier means obsolete. all methods have their ways,  have their relevance at different situations and times.