Here's a challenge for the whole community:
Over in the Getting Started section, we have a numismatic reference list that has lived on Money.org for quite a while. It's a good list, but it's a little stale (it was put together many years ago) and a little incomplete (it's mostly U.S. coins with a few world coins).
Here's your challenge -- start a thread for the area of your choice (ancients, world coins, exonumia, etc. etc.) and list books you believe would be most useful to someone just starting out in your particular area of expertise. We'll pull the suggestions together here at HQ and update that list as y'all add content below.8 years ago