Watson always had an acceptable excuse for this, of course. There simply wasn't enough time, or the details of the case were classified or the mystery involved persons so distinguished the tale simply could not be put to paper during Watson's lifetime due to national security interests. Or, the case notes were locked in a vault in the bank.
Both the guides are well developed characters, fascinating in and of themselves and keep the story going even during long, rather dry stretches of travel. King uses them as vehicles to explain Arabic and Bedoiun culture, but thankfully the pair never become caricatures of themselves, a tricky feat King pulls off exceedingly well.
Those who have studied Middle Eastern history or culture (I should admit here that I did, both before and during college, and of course afterwards to the extent I can) will appreciate King's discernment in what she chooses to highlight and use during the course of her novel.
The mystery itself was pretty good, though not great by mystery reader standards, laden with international intrigue and coated with a likely bitter resentment that stems from the fallout of World War I. There is a fun, but subtle, reference to Moriarty (though he has nothing to do with adventure, of course) that readers of the Canon will appreciate.
I found Sherlock to be, as usual, as close to himself as can be expected in a pastiche and Russell's religious devotion and passion softens the edges of both their cold, analytic minds.
The passage in which Russell describes seeing the Dome of the Rock for the first time from a hill above Jerusalem, as a Jewish woman, is beautiful and moving. But at no point is Russell proselytizing, either.
Perhaps the next installment.