Galaxy Books/Publishing was once a bustling enterprise. The Galaxy Novel series, ran for 31 editions as digest-sized paperbacks. Then there were four more (#32–35) produced in the standard paperback-size of the day, aka 1958. A year later, Beacon Books continued the series with eleven more editions in paperback-size that extended the series through 1961.
And finally, in 1963, a short-lived series of three digest-sized book/magazines appeared. Dubbed a “Magabook” each edition included two compete novels. The first was The Sky is Falling and Badge of Infamy, both by Lester Del Rey, with cover artwork by Virgil Finlay.
Both series of digest-sized novels are covered in depth by Steve Carper and Gary Lovisi in TDE4.