After two years of active neutrality (August 1914-August 1916) Romania entered in WW1 to fulfil her national State unity. The authors, two leading Romanian military historians, using the results of 20 years of archives and libraries’ research, provide an objective analyse of the events, a valuable reference to the general context and particularly to the Romania’s diplomatic and military involvement, in relation with the Eastern and South-Eastern European fronts. Throughout the volume they put an accent on the military aspects, pointing on the arguments of strategic planning, the operations’ development in connexion with the other battlefields, with a special outlook to the cooperation with Russia and its consequences after the collapse of Russian front in fall 1917. The authors reason that Romanian resistance in 1917 against the Central Powers had been the only Entente important success. They emphasize that Romania’s Great Union in 1918 with her major provinces Basarabia, Bucovina, Transylvania and Banat was the outcome of titanic political, economical and military endeavours to the common Allied victory. This volume could be considered as an essential overview to the subject.