Wikipedia has a good piece in infiltration tactics

Again, Wikipedia has a literate piece on a subject. This time, the topic is infiltration tactics. We find that a French officer had described the tactics in a pamphlet published in 1915. The Germans captured a copy in 1916, and recognized that this was a "breakthrough idea". The Germans only used infiltration for the first time in September 1917, on the Eastern Front. They used an infiltration-based attack to raise the seige of Riga. In October 1917, Rommel participated in an infiltration attack on the Italian front, which was very successful. Rommel was involved with these ideas very early in their introduction. They formed the basis, really, for the rest of his military career.