Q:

"as written by" vs. "written by"

What is the meaning of as in as written by?
(I've searched everywhere, including many dictionaries, and I've googled it, but there isn't the slightest sign of what that as means, and I thought that no definition for as was proper in this situation.)

Is written by a shortened form of as written by? That is, does it always literally mean as written by, but sometimes we shorten it to written by? If not, what is the difference?
Which one is better to use in the following sentence?

... my prescription information pamphlets as written by [or just plain written by] my father.

A:

One of the meanings of "as" is "in the manner or role specified" (see Wiktionary). So "my prescription information pamphlets as written by my father" means "(...) in the manner that my father wrote them" (with regard to formulation or other characteristics). This is a formulation that can be used if there is a discussion about the way in which they were written or about their content. 
However, "the prescription information pamphlets written by my father" is a way of identifying a specific set of documents among a larger set. There may be similar documents written by someone else, but you want to talk only about those written by our father. (Note: I replaced the first "my" with "the". However, "my prescription information pamphlets, which were written by my father, ..." would work in a different syntactic context.)
So "written by" and "as written by" serve different purposes and cannot be used interchangeably.

