From what I see at [this wiki page](https://en.wikipedia.org/wiki/Armenian_language), these two versions of Armenian show differences in phonology and sometimes in grammar which are greater than, say, a difference between Russian and Polish (and quite close to that between Finnish and Estonian).

So, are books written in each one of these two dialects equally intelligible for a speaker of each version of Armenian? Or is there one-direction understanding (as it is the case with Estonian speakers, who can intuitively understand most of spoken and written Finnish, but whose speech is hard to be deciphered by an unprepaired Finnish speaker)?