I had what I believe was the first Quiller book on my shelf for years and I finally gave it away. I couldn't remember why I never got into it. I found this one in a pile of recycling and refuse at the corner of the school near my house. It was being thrown out with a bunch of other books from the library. I started reading it and I think I know now why I never got started with the other one. If The Tango Briefing is any indication of the Quiller series, it is some pretty hardcore nerd-espionage. Nothing can be simply done without Hall explaining in insider espionage language the background, the ramifications, the various potential outcomes, several other instances of the same maneuver having been done (generally unsuccessfully) and how it will impact the behaviour of the "opposition". It's kind of like reading about a football game where each play is prefaced with a litany of statistics and comparisons. It's cool if you are into that sort of thing, but can be a bit trying for the reader that just wants some football action. In case you think I'm exaggerating, the act of flicking a lit match into a car's gas tank takes over two and a half pages of explanation!
Furthermore, he writes in an almost poetic style at times, using incomplete sentences and jumping around in time without being really explicit about it. So if you aren't paying close attention, it can be easy to get lost and not even be clear where the protagonist is geographically at any given point. This reader was not paying close attention in the first third of the book or so. However, once I did finally get an understanding of his style and once I got caught up in the story, I did pay closer attention and actually got quite into.
My critique above are not really criticisms, because Hall is a skilled writer and the story that goes down was really cool. It's simply a question of personal preference. You see some popular modern writers try to write like this (Jeffrey Deaver comes to mind and Lee Child as well). Once you read a Quiller book, their efforts seem sort of cartoony and overblown. The Tango Briefing was intense. The story centers around a mysterious marking in the middle of the Algerian desert, some kind of aircraft, discovered by British surveillance. Quiller is sent out to establish a base and make his way to the aircraft without being discovered. Unfortunately, when he gets to Algiers, he finds that two previous agents ("executives" as they are called) have already been compromised: one killed and the other a broken, nervous wreck after having been followed by a sniper for several days. Just the process of setting up a way to get to the aircraft in the desert takes up about half the book, with Quiller negotiating every step to lose "tags" (people following him) and avoid alerting listening posts and other sensitive alerts that make up the world espionage network. The "opposition" is so faceless that it might as well be a computer network.
When he does get to the desert, he has to find the wreck, discover what is so special about it and get out. The whole section in the desert is really intense and believable. It gave me a strong feeling of how frightening it would be to be exposed in the middle of the sahara where even if you had enough water, you couldn't drink it fast enough to prevent the evaporation from your body.
I'm not sure if I will rush after any more Quiller books. They are a little too detailed and complex for my simplistic mind. I would, however, strongly recommend them to anyone who considers themselves a hardcore espionage fiction enthusiast.