Lars Svensson's classic “Identification Guide to European Passerines”
was first published a few decades ago. It is no longer available from
Amazon, but I have been keeping an eye on copies from other sellers on
the Amazon marketplace, and I am increasingly puzzled by their proposed
prices.
The absurdly high price isn't because the book is new, because there's a
used copy for sale at $1847.20. Even the cheapest used copy right now is
priced at $458.60, and that's still far more than I can imagine anyone
wanting to pay.
The sellers don't look shady at first glance, and many are highly rated
over a significant period. Maybe they didn't notice that the book is
available elsewhere for twenty-odd euro? But no, it's probably an
“algorithm” (note: those are scare quotes) at work.