This book is probably the most recommended reference for currency collectors - and rightly so. It is the origin of the famous Fr. numbering system, by which dealers and collectors label their notes. The book is worth its weight simply for the Fr. numbers. This book also covers nearly every nook and cranny of US currency, including background history, values in varying conditions, and large images to whet you appetite.

The Standard Guide is a must have for Small-Size collectors. It breaks down notes on a run-by-run basis or by FRB/block combinations to give extremely detailed analysis including lowest/highest know serial numbers, production numbers, and value in varying conditions. This book covers all Small-Size categories except National Bank Notes. Nationals, alone, require a reference book of their own.