I read this book about 15 years ago and am reviewing random books I read a while ago in order to create a body of reviews on the site. Ada or Ardor is an interesting book, although probably (almost certainly) not the best book to start with if you intend to read multiple Nabokov books. I think I read that he specifically intended to shake off the insufficiently dedicated with the somewhat confusing first chapter. It is the third in an implicit trilogy of sex-perversion novels, preceded by Lolita and Pale Fire, and has the most unusual setting; Lolita can and probably should be interpreted as happening in the real world, insofar as any fictional world can be so interpreted, and Pale Fire could be in an alternate universe or could be the ramblings of an insane person. Ada is definitely in an alternate universe, where Russia is in America and we are all together goo goo g'joob. The overt plot concerns itself with an incestuous romance among noble Russmericans who engage in the sort of dissolute lifestyle commonly engaged in by a more-or-less openly corrupt upper class in the late 19th/early twentieth style; lots of affairs, lots of gambling, visits to prostitution dens, and so forth. The thematic plot is memory; I won't spoil anything intentionally, but childhood nostalgia is intertwined with the sex, along with a lot of regret about unfortunate choices involving now-dead relatives and also a large overt/covert commentary/plot point about access to the 'real world' in a sort of spiritualist way (late 19th/early 20th century is definitely a thematic theme and this stuff about our world had a strong tinge of that to me; I have seen this book mentioned in academic reviews of science fiction so it seems to have given a science fiction vibe to some people but I interpret it in a generically spiritual and specifically Spiritualist way.) It's Nabokov's longest book and possibly his most self-indulgent - if you like Nabokov, read it; if not, skip; if you don't know whether you like him, he has several shorter and easier books with which you can make up your mind. I was basically down with reading it, and enjoyed it, but there was a dash of completism in my motivation.