Young wife is murdered.
Older, gentleman husband
Seeks truth in Kenya.
I'm a big John Le Carre fan, especially of the Smiley books (most notably The Spy Who Came in From the Cold and Smiley's People).
And The Constant Gardener came highly recommended: Elizabeth George wrote in Write Away that Constant Gardener made her feel inadequate, that Le Carre is "a genius ... a superb stylist, a brilliant technician, an incredible creative artist."
So, yes, I came into the book with very high expectations.
In some ways, I wasn't disappointed. The characters are fascinating: fully developed, clearly still growing (or refusing to grow), mixtures of good and bad, capable and incompetent, brilliant and stupid. And the general plot was intriguing: the do-gooder young wife of an older British Foreign Officer in Kenya is brutally murdered. Rumors fly: she was having an affair, her lover killed her, etc. etc., and her husband wants to find out what really happened.
First, the ending was clear early, early on. I understood in about the first quarter of the book who arranged the murder and why, but it took Justin (the husband) another 300 pages to track down people who could tell him what I already knew.
Second, it was a slog. It took me weeks to finish this, and I had to force myself to keep going. In fact, this is the novel that convinced me to buy into the 50-page rule: if a book hasn't hooked me in 50 pages, from now on, I'm putting it down. My life is too short (and my To Be Read shelf too crowded) to waste time on books that drag.
Third, it was confusing. There are certain expectations a reader has, one of which is that the point-of-view character in the first chapter is the main character, the protagonist. But the first six chapters are (more or less) in the POV of a minor character: important to the plot, but not to the story. I kept waiting for that character to take his rightful place as the hero of the story.
Oddly, this is the second book I've read recently which features a nonstandard narrator (omniscient, for lack of a more accurate word) who followed a secondary character's POV for the first six chapters. But in the other book, at least I understood the reason for the choice. I haven't the vaguest idea why Le Carre chose this nonstandard, confusing beginning.
Overall, the book was a crashing disappointment. Though I loved Justin and Tessa Quayle, I mostly resent the hours and weeks I spent wading through their story.