Smith, E.E. "Doc": Skylark Three - v 1 - 21 May 07
The last of the PD Doc Smith books that I have found, this one was published in three parts in 1930 as the sequel to The Skylark of Space.
All of the original covers are included and of special note is the one just before the start of Chapter VII that shows the then recently completed Chrysler Building in New York City.
This was written before the great "Lensman" series which incorporated parts of this book into it.
The original had 54 downloads.