This appendix contains detective tasks previously published in the journals "Science and Life", "Shield", "Tasvir", "World of Crime", etc. The solution of these problems will allow to develop attention, observation, intelligence and resourcefulness ...These tasks are loved by all and at all times. Some see them as a kind of “gymnastics of the mind,” a means of satisfying the natural need for every thinking person to experience and exercise the power of their own mind. Others are attracted by the elegant literary shell: the plot of logical tasks is often quite entertaining. Still others consider their accessibility as the main advantage of this type of task: you can often hear that solving logical problems requires not special knowledge, but only a certain level of development, the ability to think logically, acquired and developed, like any other skill, persistent exercises.