I have added to my site:
http://augustuscoins.com/numislit.html
some of the most interesting ancient-coin sale catalogs, including one with 482 coins with river gods, one with an EID MAR in gold and many other coins of extremely high value (would make a coffee table book!), one with 641 high-quality Roman provincial coins in color, a group of Tkalec catalogs where many types are common but almost all the coins are EF+, and NAC catalog with an excellent selection of late Roman gold, Germanic migrations Dark Ages, Byzantine, and early medieval.

There is lots more there, including the finest book on eastern Celtic coins and many other books and catalogs arranged by collecting theme.

If you prefer coins to books about them, see my page here:
http://augustuscoins.com/index.html

One of the coins for sale is this coin of Antoninus Pius without the title of Augustus.




Struck very early in his reign when he was still negotiating with the Senate about deifying his adoptive father, Hadrian.

The coin pages, again, begin here: http://augustuscoins.com/index.html