What? I think I am getting you wrong, for this seems so simple! Everyone quotes people, in journals and in books.... if it's a direct quote you put in page numbers...one would die if everyone was to seek permission from every person they directly quoted... imagine the sheer hassles it would involves, I cant even begin to think!!
But obviously i guess that is not what you mean,...if you intend using other people's data, reproduce their images etc, then of you are publishing a book you would need permission I think...