This is the third and final book in the Duke’s Heiress series. I chose it because I remember enjoying the author’s Seducers series back in the early 2000’s. The hero of this book is Nicholas Radnor, the Duke of Hollinburgh, who inherited his title and lands when his eccentric Uncle Frederick died by falling off a roof. Not only does Frederick’s death seem suspicious, rather inexplicably, his uncle left his fortune to three young women.

The story opens when beautiful Iris Barrington comes to see Nicholas at his London home. She’s there to request that he fulfil a promise made by his uncle to help her find a special manuscript, a Psalter, that was bought by Nicholas’ grandfather. Nicholas can’t believe his luck when she appears because Iris is the third heiress he and his cousins have been searching for. Iris is surprised when Nicholas tells her she has inherited a fortune from his uncle. She will have to prove her identity before she can receive her inheritance which will take a few months.

Iris finds a small book store near the British Museum that reminds her of her home in Florence and she leases an apartment above the book shop. She and Bridget, the owner, help each other and work to purchase books at auctions. Bridget is a fun character but it’s her feisty cat, King Arthur, that steals the show. Iris and Nicholas meet again at an auction and he saves her from being run over by a runaway carriage. There are more attempts on their lives, even some poisoned lemon tarts, but they are not sure which one of them is being targeted. Together, they must work to solve both the mystery of Frederick’s death and of the threats to Iris.

Iris is a wonderful character. She is intelligent, especially with her dealings in rare books and art. Nicholas admires Iris but doesn’t quite trust her. He hires her to catalog his library, which gives them a chance to get to know each other and makes it possible for Iris to look for the missing book that she believes is part of his collection. It was wonderful to watch Iris discover and deal with valuable books and art. For her part, Iris admires Nicholas tall, ‘exceedingly handsome’ looks.

Nicholas has a large family with matchmaking aunts. They throw a house party and include Iris, and the other two heiresses, Rosamund and Minerva, whom Iris has become friends with. Iris sees it as a way to continue her search for the Psalter. It is wonderful to watch Nicholas become closer to Iris both emotional and physically, especially when they spend an afternoon swimming in a pond. There is also a beautiful and very wealthy heiress, Miss Paget, that Nicholas’ aunt Dolores invites to the house party in the hopes that Nicholas will propose to her, which causes problems for Nicholas and Iris. Miss Paget has a massive dowry and Iris knows that Nicholas needs money to run his estates. Also Miss Paget is part of the aristocracy, and Iris is not.

I found myself rooting for Nicholas and Iris but I was wishing I had already read the first two books in the series so I would be more familiar with Nicholas’ family. It is a large family and sometimes it was hard for me to keep track of who was who. The ending felt a little abrupt; I hoped to see a little more of Nicholas and Iris once they were a couple. I did like the twist at the end and enjoyed all of the mysteries in this story as well as the slow burn romance. I recommend this for readers who like historical romance with a mystery.