James Bond has come to a crossroads in this book. He's seriously thinking of quitting and goes as far as composing a bitter resignation from the Secret Service. He's restless, unhappy and is looking for ...something. And then he meets a girl. In the middle of a romance that surprises and even scares him a little Bond gets handed an asignment that turns out to be far more complicated than even he could've dreamed. Blofeld is back and this time their encounter becomes personal.
If you saw the excellent movie then you know what happens.
Ian Fleming did a fantastic job with the sublte foreshadowing. Bond meets Tracy in the same town where he met Vesper Lynde in Casino Royale. We learn that he's been visiting Vesper's grave once a year for years. It reminds the reader that Bond does have a heart and it can be moved. Later, Bond, to his chagrin realizes that he wants to wrap this Blofeld business up mainly so he can get back to Tracy.
In addition to this, the usual Bond trademarks are here. You have a horrifying villain, revolting flunkies, glorious scenary, a desperate chase that almost gets Bond killed and an unforgetable ending.