Well, the manual is nice for reminding yourself how the interface works. But it doesn't provide much else to help you play the game better. Strategy guides and actual experience might be more useful.
Oh, and the glossary says that the Skyrangers are leased from the Russian Air Force. What's that got to do with anything? Um, I dunno.
But seeing as these are not in the manual, here are some things that you wouldn't have spotted without a bit of experimentation (or at least I don't recall seeing them in the manual):
Pressing any key on the keyboard toggles the text overlays for the globe in the Geoscape. (Anyone who's played the game for some time will have spotted this one by now)
Clicking on the zoom buttons in the geoscape will increase or decrease magnification when you click on them with the left mouse button right? The right
mouse button will set it to its respective maximum zoom level. Not particularly useful, but it can save you a few clicks.
In the dos version of UFO and TFTD: ctrl+backspace makes a copyright symbol. I suppose this is more of a bug than an actual game feature.
NKF, narrow minded fuddy duddy who refuses to let go of the past and will not accept anything newer than 1979.