While I did enjoy "Ancient Shores," it was not my favorite of McDevitt's work by any means. The idea was quite sound: a boat made of materials that simply shouldn't exist is uncovered in a farmer's field. Further away, a building that grants a new type of technology - and a new way to travel - is uncovered. But from there, the book got a little scattershot and random.
We follow many world reactions to this newfound technology - from the collapse of the stock market at the apparent use of materials that would never wear out, to religious fanatics, to the UN demanding the artifact be made a world-owned item, free of any one nationality. McDevitt certainly extrapolates the effect of technological change in this novel, and it is quite a classic approach to Science Fiction.
However, the plot withers amid all of this extrapolation. The heroine and hero of the story begin to get less and less air-time, and ultimately fizzle out near the end. Likewise, a sub-plot of a potential "alien trapped on earth" peaks interest, then loses ground to yet another tangent in the story.
For a better tale of the effects of Science and Technology on the world stage of economics and politics, try the "Red Mars," "Green Mars," "Blue Mars," trilogy by Stanley Robinson. McDevitt had a good idea here, but it just didn't quite fly as high as it should have. It was interesting, and made me think of a few new ideas, but didn't drive me to the end like his tales usually do.