Ace Double (F-299, 40 cents): 1964 paperback. Condition is VG+ to near-Fine: tight and very square with flat spine; very light overall wear including a 1" finger-crease on each side; age tanning is mild to moderate and uniform (slightly darker on inside of covers.) A number is written at upper right of each first page - no other writing, stamps, or marks - a clean copy that looks unread.

Ace Double F-299 (1964): containing Endless Shadow by John Brunner, bound with The Arsenal of Miracles by Gardner F. Fox . This is the first paperback appearance for either novel.

The Brunner half, Endless Shadow (97 pages, cover by Ed Valigursky) is revised/expanded from "Bridge to Azrael" from Amazing February 1964.
Jorgen Thorkild was director of the Bridge System that connected forty worlds among the stars. Two worlds were under consideration for being added to the System: Azrael, where pain was the only reality, and murder was not a crime but a ritual; and Ipewell, where motherhood was honored, and manhood meant a life of servitude and fear. After a few words with representative Long from Azrael, director Thorkild has a breakdown, questioning the basis for his beliefs. Earth's mission is to bring all human planets into the Bridge - will these two prove to be too hard to swallow?

This was expanded/revised in 1982 as Manshape. Brunner was at the top of his form in the late Sixties/early Seventies and I've found that any rewrites he did then were excellent. I'm not sure about rewrites from the Eighties - not having sampled any of those. I have read this version and I do recommend it.

The Gardner F. Fox book, The Arsenal of Miracles (156 pages, cover by Jack Gaughan) says "First Book Publication," but I can find no story it was based on or earlier appearnace.
When Earth's stellar empire was attacked by the Lyanir, a powerful race from the uncharted stars, Bran Magannon, High Admiral of Space, met their battle-challenge and stopped them. He also fell in love with the beautiful young Lyrian queen Peganna, and his name became that of a traitor. Now he was a lone outcast among the Empire's outpost worlds, called Bran the Wanderer. Then Peganna of the Silver Hair returned and told him of a fabled cache of deadly weapons left eons ago by the long dead race of the Crenn Lir. She wanted these weapons for her people, and Bran laughed, and showed her how to find them. Gardner Fox had most impact in the Comic field starting in late Thirties. This is good space opera - colorful and full of action - and in my opinion, Fox's best book. (And Clute/Nichols of The Encyclopedia of SF agree.)