Arguably the most successful and beloved Scottish writer since Arthur Conan Doyle, Ian Rankin has much to celebrate. He turns 47 later this month and, with the publication this week of “The Naming of the Dead” (Little, Brown,; 452 pages; $24.99), can view with pride his 20th novel in the superb series featuring John Rebus, who got his name from the picture puzzles that were once so popular.

It is difficult to describe the many points of significance and excellence in these books.

First, they are set in Edinburgh, which most Americans (me included) have generally regarded as a friendly, attractive, and benign city, offering lovely shops on Princes Street, a formidable and handsome castle right in the middle of everything, and a smiling, polite populace. The only truly terrifying thing about Edinburgh is the prospect of encountering haggis, the Scottish culinary blight consisting of sheep’s “pluck” (heart, liver, and lungs) chopped with flavorings and boiled in the animal’s stomach.

Then Mr. Rankin showed the dark, seedy, drug-infested, violent underside of a city that hadn’t seemed to have one. The city itself plays a major role in the books, its personality and appearance as lovingly detailed as any character.

Second, there is the unprecedented success of the Rebus novels in the United Kingdon as they made it into “The Guinness World Records” when seven of his titles were on the best-seller list simultaneously. Surprisingly, despite a large number of devotees in America, they have not achieved similar heights over here.

Third is the Rebus character himself, one of the greatest of all contemporary literary figures. When we first meet him in “Knots and Crosses,” the earliest Rebus novel, he is walking to the grave of his father, who died five years earlier. As “The Naming of the Dead” opens, he is at the funeral of his brother, with whom he had an uneasy relationship, just as he has with his entire family. Not close to his sister, he lives alone after a “busted” marriage.

Rebus is “a good detective,” Mr. Rankin once remarked, “which makes him a bad social being.” He drinks too much, still smokes, has occasional affairs, and, while not cynical (though often perilously close), his world-weary posture is saved by his humor, which leans toward the acerbic.

Living in “real time,” aging at the same rate as the author, Rebus grows tired sometimes, but still likes being on the force. “Without the job,” Mr. Rankin writes in the new book, “he almost ceased to exist.”

“The Naming of the Dead” might be the most ambitious book in the series, almost too much so. There are so many elements, so much going on all at once, that only a master like Mr. Rankin could manage to get it all to make sense at the end of the day.

It is set in July 2005 at the G8 Summit Conference in Edinburgh. President Bush is there, along with Tony Blair, other world leaders, members of Parliament, and 250,000 protesters, most of whom are making a party of it, but they include small groups of anarchists and neo-Nazis who want only to create nasty mischief. Among the throng are the usual angry beautiful people — George Clooney, Susan Sarandon, Bianca Jagger, et al.) who travel in their private jets to protest fuel emissions.

One of those attending the meeting apparently commits suicide, going off the castle’s very high wall. The fact that he screamed the whole way down suggests to Rebus that, just possibly, his plunge might have had help, but his superior wants to close the case immediately.

Meanwhile, Rebus has just begun searching for the killer of a convicted rapist, though most of the force would prefer to give a special award to whoever did it. Rebus persists in his hunt for the murderer, but make no mistake: He despises the victim as much as anyone. As the autopsy is being performed on “the Rape Beast,” the pathologist tells Rebus, “No one’s born bad, John.” Rebus replies, “Well, nobody makes them do bad things, either.”

When another murder occurs, Rebus fears they may have a serial killer on their hands, and then the political wrangling intensifies, and the mother of Siobhan Clarke, his partner and protégé, is assaulted by one of the riot police, and then …

It’s a big, complex book, and getting it all tied up must have been as much of a challenge for Mr. Rankin as solving an intricate rebus.

Mr. Penzler is the proprietor of the Mysterious Bookshop in Manhattan and the series editor of the annual “Best American Mystery Stories.” He can be reached at ottopenzler@mysteriousbookshop.com.