The back cover says it all. The Berserkers are implacably dedicated to the destruction of all life, only tenacious humanity stands in their way. This is a short story collection, and frankly the short story suits Saberhagen's writing style far better than novels.
As portentous as the conceit is, the stories are not really about violent threat. What we have here instead are a series of nice puzzle boxes. You're trapped with a killer robot, how do you escape? That question is variously answered by a farmer, a historian, an archaeologist, some marine biologists, and most amusingly, by an encyclopedia salesman. There were a couple non-puzzle stories but they're paid-by-the-word filler (the messy, unfocused "Events at the Templar Radiant"; the cheesy Orpheus retelling in "Starsong").
Mostly pulp, sometimes well done and sometimes not, with 70s style and sensibility. Modestly recommended for fans of the same. Available for $2 at Dreamhaven in south Minneapolis.