William McDougall 
Group Mind [PDF ebook] 
A Sketch of the Principles of Collective, Psychology With Some Attempt to Apply, Them to the Interpretation of National Life and Character

Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. I would gratefully confess that the resolve to go forward without a further long period of preparation has been made possible for me largely by the encouragement I have had from the recently published work of Dr. James Drever, Instinct in Man. For the author of that work has care fully studied the most fundamental part of my Social Psychology, in the light of his wide knowledge of the cognate literature, and has found it to be in the main acceptable.