R.W. Thompson 
Montgomery the Field Marshal [PDF ebook] 
A Critical Study of the Generalship of Field-Marshal the Viscount Montgomery of Alamein, K.G. and of the Campaign in North-West Europe, 1944/45

This book, first published in 1969, examines the achievement of Montgomery and the 21st Army Group in the campaign in Northwest Europe in 1944-45. The author observed the campaign first-hand, and has spent twenty years poring over war diaries and regimental papers to provide an in-depth analysis of Montgomery’s generalship, personality, complex relations with his American allies, and his own subordinates. Looking at Montgomery’s performance as a morale builder both for troops and civilians, this books also examines his difficulties with the diplomatic niceties of coalition warfare.