"Operation Horror" by Murray Leinster is an exciting science fiction novel about the audacious plan of terrorists from the future who decided to change history by interfering with the events of the past. The main character, the inventor Reginald Blaine, finds himself at the center of mysterious crimes and must stop the terrorists in their plans at any cost. A frank violation of the space-time continuum leads to incredible events and unexpected turns of circumstances. "Operation Horror" captivates with its intense atmosphere, sophisticated plot and skillful combination of scientific discoveries and adventurous spirit.