This is a frothy Cold War thriller based on a neat premise, namely that a bus tour of Europe is a great way to conduct espionage under deep cover. The blurb is particularly effusive:
...it will be quite obvious to him [sc. the reader] that the author is himself an experienced traveller and at the same time is very well informed about the niceties and details of practical espionage -- which is hardly surprising, for Don Betteridge is the pseudonym of the knowledgeable writer of travel books and spy stories, Bernard Newman.
After the mysterious demise of their predecessors, Captain 'Tiger' Lester (an "ace operator") and his determinedly virginal assistant Madge ("Midge") Parker ("an expert in Judo"), are sent undercover to work out what went wrong. The book is full of cringe-worthy dialogue:
"You're a good scout, Tiger.""Oh. Why?""I take it that our marriage is on a purely friendly basis, as usual.""Of course.""Not every man would say 'Of course'. Some would forget the job they're on. You don't -- that's why I like working with you."
The two end up on another tour ('In the trail of the Three Musketeers') with Lester the guide and Midge the innocent tourist:
"Your friend Bernard Newman wrote a book some years ago, In the trail of the Three Musketeers... Here it is. Forget everything else - just wallow in this."
The settings are nicely done but the novel too wallows about - in sinister Russians, dodgy scientists, a spot of amateur philately, and a deadly weapon called the Destructor locked in a theft-proof lab in Harrogate.
This lazy book is a complete load of old cobblers, but I suspect that's why I enjoyed it, despite the frequent cringing. It is a good premise and I was reminded of a short-lived TV series in the 1980s based on a similar idea - Masquerade - where a bus-load of tourists unwittingly possesses the skills required for high level espionage (think Mission Impossible on a bus). I don't think Kirstie Alley will have it anywhere near the top of her CV.
If you liked this... there's no hope for you. Only kidding: how about - and a million times better done - anything by Helen Macinnes; perhaps Prelude to Terror (1978) for its mix of professional and amateur spies.
PS Helen Macinnes does not deserve to be out of print.