Asimov has balanced the demands of [two genres, mystery and science fiction] by building on their common ground.

Both types impose the need for logical, analytical method and for subtle, acute reasoning—applied in the one instance to untangling a puzzle in immediate time and place, the other in speculative time and place. Both exercise the special knowledge of the author. Detective fiction demands a knowledge of police procedures and an understanding of the deductive process; science fiction, of the scientific premises on which the speculative world is based.

A second answer lies with Asimov's own track record. He has been able to draw on his ingenuity without undue strain or awkward repetition. In at least three cases he has expanded an initial appearance of his detective characters into a series without sacrificing either his powers of deduction or his scientific reasonableness. The last four of the Lucky...