The Hound of The Baskervilles

One of Sherlock Holmes’s defects – if, indeed, one may call it a defect – was that he was exceedingly loath to communicate his full plans to any other person until the instant of their fulfilment. Partly it came to doubt from his own masterful nature, which loved to dominate and surprise those who were around him. Partly also from his professional caution, which urged him never to take any chances.
from Sir Arthur Conan Doyle “The Hound of The Baskervilles”