Frank Tallis’s sixth adventure for his Viennese psychoanalyst, Deadly Communion, (Century, £12.99) is heavy on the psych and not much cop, frankly, on the analysis — I had the murderer pegged halfway through.

Not only that, but Tallis’s eagerness to pin the crime on the, er, donkey, requires a stunt so wildly improbable that it would be bizarre even if carried out in the present day, let alone in the more staid, 19th-century Vienna.

But fans of the Liebermann Papers series, with young and handsome Dr Max Liebermann trailing alongside his fat cop friend Detective Inspector Oskar Rheinhardt, will find plenty to enjoy — although it has to be said that Max’s obligatory visit to his mentor, Sigmund Freud, lies heavy on the page. Tallis has spoken before about Freud’s fondness for telling jokes but if these samples are anything to go by then Freud’s career as a stand-up comedian was always a non-starter.

This time Liebermann and Rheinhardt are trailing a sexual predator with a very particular method of killing.

Eventually the pair, together with the woman for whom Liebermann has been feeling on-again-off-again passion for the last five books, Amelia Lydgate, assemble in the pathologist’s lab — as you do.

Freud’s career as a stand-up comedian was always a non-starter

English-born Amelia, with her unusually early interest in forensic methods of solving crime, provides some interesting answers — but oh, Lord, this romance is tedious. Please, Frank, either get Max and Amelia together properly, or get rid of her.

In a long series of acknowledgments at the end of the book, Frank Tallis, himself a former practising psychoanalyst, pays lengthy tribute to the sources providing the intricate psychological ideas discussed in the book.

But, for this reviewer, such information lends weight to the feeling that the Liebermann Papers have become closer to text books than novels. The narrative driving this outing is almost beside the point.