334 - Mode of Issuance

This is a tag that came into the MARC record as part of RDA. 

It is defined in BF&S as "Mode of issuance of the manifestation being described" which is not super helpful. The tag must contain a term (in subfield a) from the RDA Mode of Issuance Term list which makes things a bit clearer. Some of the terms on the list are "published" (and thus, usable) and others are "deprecated" (no longer to be used).

There are actually only 2 currently valid choices for what can go here:

• "single unit" which is "a mode of issuance of a manifestation that is issued as a single physical unit or intangible single logical unit." Basically one object (a book, a CD, a map, a digital file, etc.)
• "multiple unit" which is "a mode of issuance of a manifestation that is issued as a multipart physical unit or intangible multipart logical unit." In other words, something that comes out in multiple pieces, like a serial or a multi-volume set of books.
  

Subfield 2 contains the "Source of term" code, which will be rdami.