This is really good! No, I didn’t think to look for the preface for the entire work. Thanks for raising this. It’s probably okay for us to quote some passages, though I’d be hesitant to post the whole thing from Libgen for copywrite reasons. (We have the license to post the version we’re posting, but I’d be surprised if Cambridge press was as permissive.)
Wikisource has several 19th century translations of the preface, eg, Spedding 1844.