The term "bend sinister" means a heraldic bar or band drawn from the left side (and popularly, but incorrectly, supposed to denote bastardy). This choice of title was an attempt to suggest an outline broken by refraction, a distortion in the mirror of being, a wrong turn taken by life, a sinistral and sinister world. The title's drawback is that a solemn reader looking for "general ideas" or "human interest" (which is much the same thing) in a novel may be led to look for them in this one.
Vladimir NabokovBut as Van casually directed the searchlight of backthought into that maze of the past where the mirror-lined narrow paths not only took different turns, but used different levels (as a mule-drawn cart passes under the arch of a viaduct along which a motor skims by), he found himself tackling, in still vague and idle fashion, the science that was to obsess his mature years - problems of space and time, space versus time, time-twisted space, space as time, time as space - and space breaking away from time, in the final tragic triumph of human cogitation: I am because I die.
Vladimir Nabokov