Inspector French's greatest case

Inspector Joseph French made his debut in this 1924 mystery, and he's unlike any detective before him. No flashes of intuition, no dramatic confrontations, just relentless, methodical patience. When a diamond merchant's head clerk is found dead beside an open safe in London's Hatton Garden, and valuable diamonds have vanished, French must unravel a knot of contradictions across Europe. The trail leads from Southampton to Amsterdam to Switzerland, through ciphered messages, false clues, and the cold logic of railway timetables. The brilliance of Crofts' puzzle lies in its fairness: every clue is presented to the reader. The satisfaction comes not from dramatic revelation but from watching a brilliant mind work, slowly, surely, eliminating the impossible until only the truth remains. This novel established Crofts as one of the "Big Four" of the Detection Club and created a detective who would endure for decades. For readers who love classic fair-play puzzles and the quiet triumph of seeing a case solved through sheer intellectual rigor.