What a tangled web. Secrets of a Lady was one of Tracey Grant's earlier books. It is about characters named Melanie and Charles Fraser. It precedes most of the Malcolm and Suzanne Rannoch books in terms of original publication. Yet in terms of historical chronology, this book takes place late in the sequence. And yet many of the things that happen and secrets revealed occur early in the Rannoch books. Chronologically, this is the first book about the Frasers but the second book published.
The Frasers and the Rannoch's are the same characters with minor differences. Most of their family and friends are the same. Some of the secondary characters have different names, but many have the same names such as Colin, Jessica, O'Rourke, Laura, Blanca and Addison. TG herself makes a comment that it is like an alternate dimension or parallel universe or some such.
The difficulty is in trying to find an order to read the books and TG offers suggestions but even so there are problems. Secrets of a Lady is a spoiler to many of the Rannoch books. It tells much of the characters' histories in one book where in the Rannoch books, many of the revelations take place spread out over the series. And there are a few differences in the stories.
I think this story is excellent and it certainly has a good twist at the end. Like the Rannoch books, much of the text is about relationships as opposed to story progression. This is where the problem is. As mentioned earlier, the relationship story including backstories is much the same as in the Rannoch books, but it is revealed more quickly. The point is, if you read this first, you spoil many of the fine twists in the Rannoch books. If you read them first, as I did, much of this book is old news. Very much.
Since this book was written many years earlier, I think it lacks some of the polish and depth of the Rannoch books. There is hardly any of the double meanings and deeper meanings which they contained. The Rannoch books frequently juxtapose things occurring in Malcolm and Suzanne's life against things happening in the lives of their friends as a sort of irony.
I didn't like Charles and Melanie as much as Malcolm and Suzanne. There is at least one major event in Charles backstory which is different from Malcolm's and I think that makes his character slightly different. As to why I like Melanie less, I can't put my finger on it. Perhaps my preference is artificial and non-existent.
In short, my recommendation would be that a new reader start with the Rannoch books such as Vienna Waltz and especially Imperial Scandal and so on, and not read this book at all. I don't think this adds enough to their story and some of the differences in detail are hard to keep straight. In some ways those differences are minor but in some ways they are not. To me, Kitty is a major difference.
Mature themes: There is backstory description of war related rape which is particularly vicious and includes an 8 year old girl. There are other atrocities against preteen children including one by the judicial system. There are many descriptions of non-sexual physical violence including killing which are not unusual in a book of this type. There is no description of consensual sex.