Publisher:Arcadia House

Some books have a (small) number on them which isn't unique enough to be a catalog number.
Given the apparent quality of these books it also seems unlikely to be a printing number.
But (so far) no number has appeared to be large enough to NOT be a Month number, although "Power Sphere"'s printing date would indicate it's not that either.

Here's the list at the moment:

#7 	Hyperspace, Jul 1966, $3.25, 188pp, hc 	R. L. Fanhope 	
#9 	Crimson Planet, 1966, $3.25, 191pp, hc 	John E. Muller 	
#10 	Barrier 346, 1966, $3.25, 191pp, hc 	Karl Zeigfreid 	
#3 	Uranium 235, 1967, $3.25, 192pp, hc 	John E. Muller 	
#4 	No Way Back, 1968, $3.50, 191pp, hc 	Karl Zeigfreid 	
#6 	Power Sphere, Sep 1968, $3.50, 192pp, hc , cover: Herbstman 	Leo Brett 	
#11 	Radar Alert, 1968, $3.50, 192pp, hc 	Karl Zeigfreid 	
#8 	Survival Project, 1968, $3.50, 192pp, hc 	John E. Muller 	
#9 	Exiled in Space, 1968, $3.50, 192pp, hc 	Pel Torro 	
#6 	The Man From Beyond, 1969, $3.50, 192pp, hc , cover: Jonas 	John E. Muller
#3      Galaxy 666, 1968, $3.50, 191pp, hc                Pel Torro
#2      The In-World, 1968, $3.50, 189pp, hc, cover Herbstman             Lionel Roberts