Instincts of the Herd in Peace and War is an wonderful book devoted to psychology which was published for the first time in 1919. The author of the book supports the thesis that simply the fact of being a social person adds certain traits to our individual and collective consciousness. Instincts play an important role in the process of making group decisions. Trotter compares such characteristics with the traits of some other social species including wolves, dogs, bees. Moreover, a great section of the study is devoted to the problems of mental conflicts and normality in psychology. Religion is also see as a result of social instincts. In general, Trotter takes some of Freud's ideas and adds a new shape to them. The book is a must have for everyone who is interested in psychology.