Are there any good references which explain the injectivity part of Grothendieck's section conjecture in details? I heard that Grothendieck himself gave a proof in the letter to G.Faltings. But I need more kind explanation.

I already read a book `Galois groups and fundamental groups' by T.Szamuely. I do not know whether the book contains a proof of the injectivity part or not, maybe my understanding is not enough.

Any suggestion would be very helpful to me.