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Maq IIRC I paid around $50 for my copy. They come up on ebay and go for less sometimes depending on whose looking at the time. The author is an auctioneer who collected straight razors for decades....

Couldn't say on the Ritchie book as I've never had a copy. The Doyle book would be worth that to me but I couldn't speak for anyone else.

If you can find a copy of "Collecting Straight Razors" by Robert Doyle it is a very good book.