Author. Traveler. Contemplative. Colorado raised. Seeker of beauty, of truth, and a great beer.
The image is as powerful as anything in science fiction: an artificial, constructed world—a spinning ring orbiting a star at an incredible speed, its dimensions measured not in the thousands of miles (as Earth and its sister planets are) but in the millions and billions of miles. The inner surface of the ring looks similar to the surface of any other earth-like world. Deserts and grasslands give way to forests and jungle. Mountains rise above the plains. Oceans, magnitudes greater than the surface area of the Earth, lap against complex, sculpted coastlines. The world seems familiar, though the sizes of each landform, of each feature, defy human comprehension.
A breathable atmosphere is held in place by rims on both of its edges, 1000 miles high. The immensity of Niven's creation represents a paradigm that every science fiction author would be wise to honor. THIS is what an author's mind can envision, when freed from all arbitrary restraint—save the nearly limitless possibilities defined by physical laws themselves. Niven's respect for the physics of his creation bear notice as well. From the rate of rotation of the ring (he gave this a precise though immense value, to ensure that the surface of the ring would exhibit a gravity similar to the Earth's), to the proposed builders' obsession with avoiding impacts with other planetary bodies—he demonstrates that someone somewhere sometime with enough energy and technology and creative will could build such a wondrous thing.
As in many other works of classic science fiction, the premise is given more attention than the development of characters in the story. The writing is somewhat emotionless and the author, at times, does not give the necessary emotional attention to the creations of his own imagination. Characters are equally devoid of real expression and exhibit only fleeting discomforts as they are faced with death or the loss of their "loved" ones.
Another critical fact (though I won't mention it here, to avoid the spoiler), having to do with the relationship of humanity to the ring, is seemingly glossed over, never explained and even dismissed. (There's even a passage of dialog between two characters that seems to have been inserted after the main story was written, probably at the behest of an editor, attempting to justify the dismissal.)
These criticisms, however, can be overlooked when compared to the shear majesty of the imagery of the Ringworld itself. This book made me nostalgic, for the SciFi of Clarke, Asimov, Le Guin, Dick and others—men and women who dared to dream big, and inspire others to do the same.