Leslie Charteris wrote several books before he hit the big time, and a few non-Saint books after. This is Leslie’s first book, published 1927 by Ward, Lock.
Crooks were trying to flood the market with "a new form of tobacco" which was very addictive. Oh yeah? Bill Kennedy of Scotland Yard was the detective who took them on, but the real hero was Terry Mannering. He sent anonymous letters (signed X Esquire) to the crooks before killing them. Remind you of anyone?

CONTENTS

I IN WHICH A GENTLEMAN OF BLAMELESS REPUTATION AND UNSAVOURY ASPECT COMES TO A STICKY END
II IN WHICH A GENTLEMAN OF CURIOUS REPUTATION AND INNOCENT ASPECT COMES TO BARRINGHAM
III IN WHICH THE PEACEFUL ENGLISH COUNTRYSIDE BELIES ITS REPUTATION
IV IN WHICH SOME JOLLY GAMES ARE PLAYED ON THE DEVONSHIRE HILLS
V IN WHICH WE REMARK THE PASSING OF TWO MORE OF THE UNGODLY
VI IN WHICH SOME DOMESTIC THEATRICALS TAKE PLACE AT MANNERING HOUSE
VII IN WHICH A PRACTICAL JOKE is PLAYED IN JERMYN STREET
VIII IN WHICH THINGS HAPPEN IN ST. JOHN'S WOOD
IX IN WHICH IS EVINCED A SUDDEN SOLICITUDE FOR MY HEALTH
X IN WHICH A CALM PRECEDES A STORM
XI IN WHICH A BUTLER is RULED OUT OF THE COMPETITION FOR THE GEORGE WASHINGTON MEMORIAL PRIZE
XII IN WHICH A THEORY is DISCARDED
XIII IN WHICH MORE HORSE-PLAY ENLIVENS JERMYN STREET
XIV IN WHICH TERRY CONTROLS HIS TEMPER
XV IN WHICH TERRY LOSES HIS TEMPER
XVI IN WHICH I AM ORDERED TO COMMIT MATRIMONY
XVII IN WHICH A WELL-LAID PLAN FAILS TO GANG AGLEY
XVIII IN WHICH A VISITOR BRINGS NEWS
XIX IN WHICH THE BEARER OF NEWS LEAVES Us
XX IN WHICH A PROPHECY is FULFILLED
XXI IN WHICH AN ATTEMPT is MADE TO FLY THE ATLANTIC
XXII IN WHICH I SEE A LOT OF THE HON. BASIL STRANGE
XXIII IN WHICH A PROMISE is KEPT
XXIV IN WHICH I TAKE MY LEAVE