SF- A Fred Saberhagen collection of 6 paperbacks as description

1. Changeling Earth ( DAW No. 41 1973)  Earth- fifty thousand years in the future, magic and witchcraft worked, Old Science didn't.

2. Stonecutter's Story. ( Orbit 1988).   Young Kasimir was the custodian of Stonecutter, the sword which could hew mountains and split diamonds - then Stonecutter was stolen and Kasimir had to recover it before it did irrevocable damage.

3. Empire of the East ( Ace 20564 1979)  A unique adventure on a world on the brink of ultimate change - a world where magic rules, and science struggles to live again.

4. The Broken Lands ( Ace G-740 1968)   Thousand of years had left Earth a series of broken lands, a mutated world of distant alien empires and near-at-hand rapacious satraps. The hunted common people had a legend, that some day one would come who would 'ride the Elephant' and bring back the Golden Age.

5. Brother Berserker ( Orbit 1975)  As the six missiles sped towards the planet's surface they disappeared.  Sentry screens placed them in probability-space, falling into the planet's past.  They stopped somewhere past the 20000 year level.  The Beserkers had discovered the potential of time warfare and unless the missiles were destroyed now, the begginings of life would be annihilated.

6. Beserker's Planet ( Ace 054651980)  The Berseker armada was broken at Stone Heath 500 years before but one of the Beserkers managed to limp to secret sanctuary on a planet called Hunter's World.  Over the years a cult arose, a cut dedicated to Death as the only and ultimate Good - Hunter's World had become a Beserker's Planet.

Condition of the books, based on the Hancer Standard, is Good to Very Good for 3 to 6 and Very Good to Fine for 1 and 2.