Right now we have "add Work" on Author Pages, "add Edition" on Work pages, "add Work" on Edition pages and finally "add Edition" on Publisher pages.

It does make sense to be able to create new entities this way, but it is fairly unclear how to link already existing entities here.
We do this by "editing" an entity and linking it in the relationship section - but this is fairly unintuitive and not obvious to new users.

suggestion: a dedicated "link $entity" button next to the "add" ones.
for this to be useful, clicking this should take you directly to the relationship section, open a "add new" dialogue and preselect the type of entity that was presented on the button we clicked.

problems:

• it's fairly obvious that this will create two routines to "edit" an entity in a way, the new suggested buttons are just shortcuts.
• secondly there are many improvements in the edit screens and how to present this data already going on, it could become problematic to do this before those were finalised
• eventually things like adding works to an edition (especially for magazines and newspapers) should have its own specialised routine that will let you make many at the same time, significantly shortening the time of adding works and making it actually possible to add things like magazines and newspapers.