About this series
The Secret Detective Agency is a series by Helena Dixon. We list 5 books in this series so far, in reading order.
The earliest book we list is Book 2: The Seaside Murders: A completely unputdownable British cozy murder mystery.
Tagged on most books in this series: British.
What readers say
Readers enjoy this wartime cozy series for its 1941 atmosphere, the Devon village setting, the tea-and-cake Golden Age feel, a favorite butler and the slowly warming partnership between the two leads, along with a gentle mystery with a few engaging twists. The audiobook narration is praised. Criticisms are that the heroine can seem rude and impatient, her smoking and coffee habits are repeated too often, the first half is slow and the ending rushed, and the many characters and code names are hard to track. Some readers find the series less polished than the author's Miss Underhay books, though later books are said to improve.
Best for: Readers who like gentle, period-detail-rich wartime cozies and can forgive a prickly lead.
Summary of public reader reviews, updated November 2026.
📖 Reading Order
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