- https://archive.org/details/onwar01maudgoog/page/n13/mode/1up Vol 1
- https://archive.org/details/onwar00maudgoog/page/n10/mode/1up Vol 3 also https://archive.org/details/onwar00maudgoog/mode/1up
- https://catalog.hathitrust.org/Record/101699011 Vol I & III
- https://catalog.hathitrust.org/Record/012204367 3 vol in 1
- https://catalog.hathitrust.org/Record/100328394 3 vol.
- https://www.clausewitzstudies.org/readings/OnWar1873/TOC.htm several “books”, also has German
Volume II appears to be missing from several archives. Several of the Hathitrust copies are U.S. access only.
This would appear to be the text in the original German, complete with archaic font: https://archive.org/details/vomkriegehinter01claugoog/mode/1up A more readable German font: https://archive.org/details/bub_gb_hjjbntg0_UgC/page/n11/mode/thumb
The first part was written by him and is supposed to be succinct, later parts were put together posthumously from his notes. According to the translator, there are nine volumes, the first three on war are the classics. His websites list eight.
[Bonus text!!! The book of five rings, the classic book of strategy by Japanese swordsman Miyamoto Musashi c 1645, tr Victor Harris: https://archive.org/details/MiyamotoMusashi-BookOfFiveRingsgoRinNoSho/page/n11/mode/1up ; other translations.]