I am looking for a multi-volume work on the Vietnam War and/or a collection of various articles by experts on specific topics of the Vietnam War, e.g., the Air War, the Naval War, POWs, etc.

I already posted a similar question a while ago. But no response, also your Wiki is pretty empty in that regard

no entry: https://www.reddit.com/r/AskHistorians/wiki/books/coldwar#wiki_asia

2 entries: https://www.reddit.com/r/AskHistorians/wiki/books/southasia#wiki_vietnam

one that deals mostly with war crimes and one that deals mostly with the South Vietnamese Army...