In Whose Dim Shadow is a 1935 detective novel written by the British author Alfred Walter Stewart, published under his pseudonym J.J.

[2] The title comes from a line in The Battle of Lake Regillus in Thomas Babington Macaulay's Lays of Ancient Rome.

It was published in the United States by Little, Brown under the alternative title The Tau Cross Mystery.

Investigations soon prove he was a leading a double life, married to two different woman and a victim of blackmail.

Sir Clinton tries to whittle down those potentially linked to the crime including the dead man's original French wife, her brother-in-law, a charismatic young clergyman and a freelance journalist.