A new book on Wilhelm II published this month honours a Sussex historian who has spent his entire academic career studying the German emperor's life and political significance.

"Thirty years of history has been the subject of nearly 40 years of research and writing," writes Professor Jonathan Steinberg in The Kaiser: New research on Wilhelm II's role in Imperial Germany. Professor John Röhl, he goes on, "found his subject in the 1960s and has not left it for four decades".

Appropriately, then, a number of his friends and former students chose to mark John's 65th birthday this year by putting together a book that examines aspects of the later years of Wilhem's rule.

Their essays highlight the emperor's relationship with statesmen and rulers at home and abroad; his role in international relations; the erosion of his power during the First World War; and his ultimate downfall in 1918.

The new volume is edited by Dr Annika Mombauer, who first came to Sussex as an undergraduate and then did a doctorate with John. It includes contributions by another three of his former research students at Sussex: Dr Katharine Lerman (also an undergraduate here), Dr Roderick R. McLean and Dr Matthew Seligmann.

Dr Holger Afflerbach, a Visiting Fellow at Sussex in spring 2001, has written a chapter on Wilhelm as supreme warlord in the First World War; and there is also a piece by Professor Hartmut Pogge von Strandmann, who taught at Sussex in the 1970s.

The book was presented to John last week (7 November) at the German Historical Institute in London. The Kaiser: New research on Wilhelm II's role in Imperial Germany is published by Cambridge University Press at £40.