In this volume (9th reprint) Mr. Bushell speaks primarily to the experienced collector, to the connoisseur, presenting discoveries, insights, and opinions derving from some two decades of research and finding cogent answers to some of the questions that have perplexed the netsuke world.
Netsuke...they're like cell-phone charms, but more artsy...way more artsy. Also, Bushell is a super authority on the subject. So I reckon if you have an interest, you'll be picking up one of his books.