The Second Boer War (1899-1902) was not only of importance concerning the domestic as well as the foreign front, but was also relevant from a military point of view. The racy development of arms technology as well as of the means of transport and communications considerably influenced warfare on both sides. As a consequence, according to international customs, both the British and the Boer forces were accompanied by several foreign officers who were tasked to study these new developments and to monitor the progression of war. This practice of dispatching such „war attachés” had a long tradition and had already been implemented in the 18th century. In the course of the Boer War altogether 20 officers on both sides took part in monitoring the operations. The reports of some of these special military attachés, such as of the Russian and French observers, have been published already. They give an insight into the warfare of both opponents and portray technical and tactical innovations. The private portrayals of war experiences by Arthur von Lüttwitz (1865-1928), the German observer of the British army, however, have been unappreciated so far. If one summarises these results, one will be able to realise that there are considerable commonalities in the reporting of the different military observers, although some individual appraisals turned out variably. Especially the appraisal of British warfare, however, the opinions differ widely. Now the reports of Lüttwitz add a German point of view to the previous Russian-American-Austrian perspective. The appraisals of the German observer concerning the condition of the British army in South Africa cannot be found in such a particularity in the hitherto sources of the observer mission. So, for instance, in his private appraisals the German observer investigated much more intensely the daily life of the officers in the British camps. Thus, the interested reader of today is demonstrated how international military cooperation functioned at the turn from the 19th to the 20th century, how international observer missions were executed, and with what kind of expectations the particular actors tackled their assignments.