Question: I've seen a pattern in a couple of titles.

* Asimov has a book called "Through a Glass, Clearly".
* Philip Dick wrote "A Scanner Darkly".
* Star Trek has the episode "In a Mirror, Darkly"
* Agatha Christy wrote the story "In a Glass, Darkly"

Curiously, 3 of the 4 are sci-fi. Any reason for the commonality of phrasing? Does it have some sort of meaning? Anyone know how it originated? Is it used in spoken English?

Answer: 
It originates from [1 Corinthians 13:12](http://en.wikipedia.org/wiki/Through_a_glass,_darkly_%28phrase%29#.22Through_a_glass.2C_darkly.22):

> 
> For now we see through a glass, darkly; but then face to face: now I know in part; but then shall I know even as also I am known.
> 
> 
>
The other answer provided the etymology, as far as the meaning:

> 
> To see “through a glass” — a mirror — “darkly” is to have an **obscure or
>  imperfect vision of reality**. The expression comes from the writings of the
>  Apostle Paul; he explains that we do not now see clearly, but at the end of
>  time, we will do so.
> 
> 
> 

<http://dictionary.com/browse/through-a-glass-darkly>