Various 
Routledge Library Editions: Group Therapy [PDF ebook] 

Routledge Library Editions: Group Therapy consists of nine titles, originally published between 1972 and 1994. It brings together authors from Europe, the UK and the US, and includes a selected bibliography of group psychotherapy for students and teachers. Out of print for some time, it is now available again either as a set or as individual volumes, in your choice of print or ebook. This is a great opportunity to trace the historical development of group therapy from a number of different perspectives.