2.5B19.

When a bibliographic volume is later expanded (e.g., a volume originally issued as v. 2 is later expanded into v. 2A, 2B, and 2C), record such expansion as one bibliographic volume in several physical volumes (e.g., <2> v. in <4>).

In recording bibliographic details for books that have been, or will be, bound by someone other than the publisher, formulate volume and illustration statements in the physical description and note areas based on the book as issued by the publisher rather than as bound after publication. For example, is a separately issued "volume 1" and "volume 2" of a monograph is bound by a library in one physical volume, "1 v." is the correct volume statement, not "2 v. in 1."

For ephemeral and "made up" sets lacking a collective title, base the volume and illustration statements on the library’s copy and binding.

See also:

2.5B. Number of volumes and/or pagination