Alias the Saint

from the back cover of the Pan Edition

(the American Edition has different stories, AFAIK):

The Story of a Dead Man: The Saint turns businessman - and runs an office which is, to say the least, unusual...

The Impossible Crime: In a room overlooking the Thames a man is shot dead, but all the doors are found locked, and it takes the Saint to solve the crime...

The National Debt: 20th-century pirates operating from an inn in south Wales have their plans upset when the Saint moves in...

... 'The Saint - Leslie Charteris's indestructible swashbuckling hero'