"Google acknowledges the incorrect dates but says they came from the providers. It's true that Google has received some groups of books that are systematically misdated, like a collection of Portuguese-language works all dated 1899. But a very large proportion of the errors are clearly Google's own doing. A lot of them arise from uneven efforts to automatically extract a publication date from a scanned text. A 1901 history of bookplates from the Harvard University Library is correctly dated in the library's catalog. Google's incorrect date of 1574 for the volume is drawn from an Elizabethan armorial bookplate displayed on the frontispiece. An 1890 guidebook called London of To-Day is correctly dated in the Harvard catalog, but Google assigns it a date of 1774, which is taken from a front-matter advertisement for a shirt-and-hosiery manufacturer that boasts it was established in that year.