A “Mushroom” Publishers example, 32 (though it says 31 on last page) small booklet 6″ X 4″,. The “Mushroom” period is a reference to the times of paper rationing during and after WWII. Ex servicemen were offered a paper ration as a “resettlement initiative” that was after books were published on any paper that could be found, some were printed on greaseproof butter wrappers, and were very short, though this example is particularly small and short.
“A THING…….
that entered houses, killing dogs with maniacal cruelty: a Thing that left absolutely no track or trace of itself: a Thing that shot men with bullets fired by a gun lying in a locked drawer…this was the problem faced by Superintendent Lakin.
I can only find one other copy for sale on ‘tinternet, as you can see I am undercutting his price. (but who is to say, we could both be over optimistic)

The Trackless Thing
P&P free to the UK
£20.00