Hi, bjk,
Somebody who knows Attic well can easily read any Koine text. In my opinion, you do not need to work through a separate Koine text book. Just start reading!
However, you may found this book helpful as an overview.
http://www.ibiblio.org/bgreek/project/f ... pre-alpha/It focuses, of course, as do virtually all "Koine" textbooks, on the Greek NT, which is a good thing!
cheers!
{ χαιρε bjk
μαθων τις την Αττικην γλωσσαν δυναται αναγιγνωσκειν ρᾳδιως την Κοινην. κατα με, ουκ εχεις χρειαν αλλου βιβλιου. αρχου δη αναγιγνωσκειν.
πλην τουτο το βιβλιον ωφελιμον εστιν.
http://www.ibiblio.org/bgreek/project/f ... pre-alpha/ ωσπερ τα αλλα Κοινα βιβλια, τουτο διδασκει την Καινην Διαθηκην. καλον δε τουτ' εστιν.
ερρωσο. }
I am writing in Ancient Greek not because I know Greek well, but because I hope that it will improve my fluency in reading. I got the idea for this from Adrianus over on the Latin forum here at Textkit.