International intrigue, phrenology and the theater (the title puns on the historical euphemism for Macbeth, i.e. ""the Scottish play"") concern Mycroft Holmes, Sherlock's older, smarter brother, in his fourth adventure in Fawcett's popular series (The Flying Scotsman, etc.). Once again Patterson Guthrie, Mycroft's secretary, serves as the Watson-like narrator. Unfortunately, for all the excitementDa threat to the government, marriage difficulties among the aristocracy, poisonings, disappearances and chasesDmany details jar. In a key plot development the ""portly"" Mycroft engages his friend, actor Edmund Sutton, who's playing the lead in Macbeth, to be his body double, yet Sutton is described as ""lanky."" There are more gunshots in central London than you might expect in Victorian times, while the official force oddly keeps a low profile. Dr. Watson can dress the wound of an admiralty runner shot on Mycroft's doorstep, then commit the unlucky man to the hospital with no fuss from the public or the police. Any mystery requires the reader to suspend disbelief to some extent, but this one at times requires a suspension apparatus that could support London Bridge. You can't help wondering why Mycroft didn't do the really smart thing and let Sherlock handle the case and Watson write about it. (Dec. 6) Forecast: Holmes purists have tended to look down their noses at this series, authorized by the late dame Jean Conan Doyle, but fans should welcome this as enthusiastically as Fawcett's previous Mycroft Holmes titles.