It sells at 342 Euros per copy for all 3 volumes, over 50 % of which I pocket myself according to the arrangements I have with my publisher.

If you are truly getting 50% of the selling price (which I in no way believe), you are gouging your readers.

Why do you keep bringing up the small income you must receive from from its trickling sales as though it were some considerable sinecure? Are you insecure about this incredibly obscure work?

Why don't you lower the price? If you really were the dedicated teacher you claim to be, you would try to make it affordable.

Lastly, though I make no claims to being any expert on Chinese, if you don't understand why I wrote xiao huangdi, then you certainly aren't one either.