The book is readily available at online bookstores including the following:
US Distributor
Stylus Publishing:
http://styluspub.com/clients/KAR/Books/BookDetail.aspx?productID=179463
United Kingdom
Karnac Books:
www.karnacbooks.com/ttlawson/jung
Amazon U. K.
www.amazon.co.uk/Carl-Jung-Darwin-Thomas-Lawson/dp/1855754681