Sherlock Holmes - The Case of the Philosopher's Ring

It's a Sherlock Holmes pastiche set in the summer before the outbreak of World War I. Holmes receives a telegram from the young philosopher Bertrand Russell, asking for his help to investigate the theft of a uniquely precious treasure - the mind of Ludwig Wittgenstein.
It's an intriguing blend of historical fiction and detective mystery, with Holmes navigating the intellectual circles of Cambridge to solve the case.