'Sommernachtstraum' was a German small-scale reconnaissance operation by elements of the 3^rd Aufklärungsabteilung of Generalleutnant Johann von Ravenstein’s 21^st Panzerdivision to the British supply depot at Bir Khirreigat in Egypt with the object of assessing the state of British preparations for an attack on Tobruk (14 September 1941).