Mikael Blomkvist is an investigative journalist who is presented with a locked-room mystery to solve, all the while seeking to restore his tarnished reputation. He is joined in the investigation by a hacker prodigy, Lisbeth Salander, who manages to get into everyone's computer with very little trouble. They run into Swedish Nazis, serial killers, and corrupt officials; they must deal with a completely dysfunctional family that, were it not for the fact that they form the core of a powerful corporation, inspire very little interest.
A locked-room mystery wrapped up inside a legal procedural tied up with a bow of journalistic intrigue. That's the premise that keeps the reader plowing through The Girl with the Dragon Tattoo despite a multitude of pointless diversions into amoral lifestyle choices.
Even were I able to write with such detail, such interesting characters, such wonderful powers of description, I'd still leave out all the sex.
It begs the question: If Stieg Larsson had left out all the pointless promiscuity, would it have sold as well? Probably not. My cynical self believes that this world is too crippled by a fascination with lust and pornography and selfish sensuality to reward authors who don't descend to that level.
Naturally, I don't include any of the youth-oriented titles such as Harry Potter because they are, after all, targeted towards family audiences who would not respond favorably to such plot diversions. I speak only of the general adult fiction that fills the shelves these days. Wandering through the shelves at the local library, one observes that there are very few modern books in the standard fiction genres (thriller, mystery, sci-fi, classic) which avoid dragging the reader through the muck.
The book, while interesting, is depressingly focused on the carnal nature of the characters, their cavalier attitudes towards marital commitment. That is, these characters don't seem to attach much significance to the concept of marriage, regarding the holy concept of physical union as nothing more than physical exercise shared by two people for whom there is a certain level of attraction. Both main characters - for there are two of them - have numerous encounters with numerous "partners". One wonders, then, if this is the nature of all relationships in Northern Europe, of if the author is simply using it as a device to attract the modern reader.
For this reader, it creates an artificially amoral chasm between the reader and the characters which cannot be bridged. The characters are neither desirable nor sympathetic. Even Lisbeth Salander, the genius hacker girl who suffered some horrible assault early in her life and was permanently marked by it, becomes simply an enigma of inexplicable logic and calculated violence. The author goes to great lengths to describe Lisbeth's casual affairs, but fails to explain with any depth the self-justification for her behaviors, except in the most banal way. perhaps the author feels that the audience doesn't have the intellectual capacity to sustain the discussion. Perhaps the author, like most other contemporary authors, is merely wishing to short-cut the process.
Entirely too much time is spent explaining the bizarre relationship between Mikael and his numerous bed-partners, one of whom is married; and the numerous bed-partners of Lisbeth, most of whom are not even acquaintances. Taking out all the tedium of these warped ideas of relationship, we are left with a simple detective story which could have been told in far fewer words.
 Method: pick out one book on each shelf, randomly flip through the 3rd quarter of the book, find the section where X seduces Y, note that it is quite graphic, sigh, put the book back on the shelf.