Disclaimer: I purchased the Kindle edition of this book in December 2018. I do not know the author nor have I ever communicated with her regarding this book or any other matter. I am an author of contemporary and historical romance.
This was a re-read, after many, many years. I'm guessing I first read Borrower of the Night in the late 1980s, though it was apparently first published in 1973. This is the first book in Peters's Vicky Bliss series. I already own books 3, 4, and 5, but I'm not sure I want to pay for book 2.
For some reason or other, I remembered Borrower of the Night as being more mysterious and less slapstick. Frankly, I don't enjoy slapstick comedy at all, and I really don't enjoy it when mixed with mystery and romance. So the silly humor in this book rubbed me the wrong way every time it occurred.
Vicky's romance with Tony also rubbed me the wrong way, and that may have been because I knew that in subsequent books, her affections got directed elsewhere. I knew, therefore, that Tony was not going to be a lasting romantic partner.
The plot is fairly straightforward: Vicky and Tony discover clues to a missing 16th century German art treasure and they set off to find it. They are joined/pursued by George Nolan, a famous art collector. The three end up in an ancient German Schloss that has been converted to a hotel. The other main members of the cast are a German physician, a German historian, the Countess who runs the hotel, her English companion, and the
countess's niece Irma who is the actual heir to the title and the castle and the treasure, if it can be found. There are various adventures and threats and accidents and injuries.
What there wasn't was atmosphere and intrigue of anything resembling a serious nature. The characters were all cardboard -- intrepid Vicky, macho Tony, presumed-evil-villain George, menacing Countess, beautiful victim Irma. I couldn't make a mental connection to any of them, and that's the main thing I read fiction for -- the characters.