By my count, this is number 21 on my quest to read all of Robert Goddard's books, in chronological order by publish date.
This one is the best I've read of his for some time. The plot is complex (with, of course, the required hallmark plot twists of a Goddard book), set in interesting and historic times, with chapters moving backwards and forwards between 1976 and 1940. The author does an outstanding job of slowly peeling off the layers of the onion of the plot, and I, at least, did not guess what was going to happen (or had happened) at any time. The protagonist in this one is an admirable character, albeit perhaps being strung along rather too easily. The characters in general are well presented and described, as are the various geographical places (Antwerp, Belgium and Dublin, Ireland, plus London and Paignton, Devon). Goddard always sucks me into his books very quickly and very effectively, and holds my attention for the entire time; that was particularly true of this one.
One skill that Goddard has is a way of writing prose that is distinctive and erudite without being pretentious. The only criticism I would have, at least in this book, is that even his non-native English speaking characters use English that would be extremely rare in those of us for whom the language is native. They all seem to speak flawless, idiomatic, and very well-constructed English.
Here's an example of his prose, chosen somewhat randomly from this book (page 103, in my paperback edition), for those of you who have yet to experience a Robert Goddard book:
"The Red Lion was still quiet at noon, the lunchtime crush at least half an hour away. The pub was close enough to Ryder Street for me to imagine Eldritch had been a frequent customer during his seven weeks of gallery-minding back in 1940. The cramped interior didn't look as if it had changed in a hundred years, let alone thirty-six. Catching my reflection in a mirror, which was difficult to avoid given how many of them there were, I seemed to see Eldritch's younger face, hair slicked, mouth curled, gazing ironically back at me.
Then the old man with the stoop and the furrowed skin and the antique suit that Eldritch had become walked in behind me. And only the irony remained, a ghost in his wary gaze."