Berkley Medalion May 1970 paperback (Putnam hardcover was 1969.) Cover by Paul Lehr, 222 pages, 75 cent cover price. Condition is near-Fine: tight and square with flat spine (very slightly dished); mild uniform age tanning (consistent with vintage); slight trace of overall rubbing (see scan.) No stamps, marks or writing - a clean copy.

A novel by Keith Laumer: The Long Twilight: Shorter version serialized as "And Now They Wake" in Galaxy March, April and May 1969. Another of Laumer's best (possibly my favorite of his) - in his serious SF thriller mode.

[Since the back-cover blurb is skimpy on details, I'm quoting from the flap-copy of a hardcover edition]:
When an experimental broadcast power station is activated - first step in bringing universal free power to all of man's machines - a weird tornado develops in the Atlantic and within hours is affecting the continent's weather disasterously; unchecked, it soon involves the whole planet in a continual, deadly storm. As the crisis continues, two strange men move into action: a federal prisoner who appears to have been serving his sentence for more than a century, and a derelict still carrying a wound from the Civil War. The prisoner escapes, the derelict rejuvenates miraculously, and both head for the power station. As they converge, police and the military set out to stop them, but cannot, and the reader discovers that these two men have met before, in many times and places, fighting a duel that has given rise to many of mankind's legends. At the end, it is for those two - born ages ago and under another star - to hazard their lives to save the alien planet that is now their home.