Return with us now to those thrilling days of the preWW I British Secret Service, when a man could legitimately be challenged to a duel for suggesting a fellow was a spy. Major Matthew Ranklin, ``with a wisp of fair moustache as ordered by paragraph 1696 of the King's Regulations but invisible at more than a few paces,'' is abruptly bumped down in rank to captain and gently eased out of the artillery troops into the Secret Service, there to encounter four loosely linked adventures. The first, a deadly skirmish over some Admiralty gold, provides him with an equally reluctant sidekick, onetime Irish terrorist Conall O'Gilroy. Then it's off to France with a dummy military code that's supposed to throw enemy agents off the scent of the real code--but ends up, courtesy of a series of hilarious complications, leaving our heroes and Corinna Finn, the American heiress Ranklin has designated as their still more unwilling helpmeet, even more bewildered. The skies are already darkening as these three agents reconvene in Germany to look into the death of a fellow agent, a mystery equally complex but much less amusing than the previous one. The final intrigue, which swirls around Hapsburg heir Archduke Franz Ferdinand in Hungary, whose empire asserts a code of laws more venerable than those of the countries ceremoniously squaring off against each other, is played out against the long shadow of the summer of 1914. Lyall (Uncle Target, 1988) gives each of these episodes a professional sheen, but the progressive darkening from Gilbert-and-Sullivan farce to fate-of-nations portentousness is less convincing, keeping the fine individual tales from forming an equally compelling novel. So ignore, if you can, the road to Sarajevo and enjoy one by one these unabashedly nostalgic chronicles from the sunniest days of MI5.