For simplicity, I have combed through the introduction and made a list of the types of lies that Ponsonby describes. These are my re-phrasings and summaries of his words:

Types of lies circulated in WWI, according to Ponsonby:

1. The deliberate official lie
2. The "deliberate lie concocted by an ingenious mind" which may only reach a small circle, but if it's sufficiently graphic, it may be caught up and broadcast.
3. The "hysterical hallucination on the part of weak-minded individuals"
4. The lie heard and not denied, that is spread by hearsay, without evidence.
5. The mistranslation
   1. accidental mistranslation
   2. deliberate mistranslation (more common)
6. The "general obsession" started by a rumor and magnified by repetition and developed into something more by imagination, which comes to gain general acceptance.
7. The deliberate forgery
8. The lie by omission of passages from official documents
9. The deliberate exaggeration
10. The concealment of truth to avoid painting the enemy in a good light
11. The faked photograph
12. The repeated news reel "to keep the wound raw"
13. The "Russian scandal": "a trivial and imperfectly understood statement of fact becomes magnified into enormous proportions by constant repetition from one person to another.""
14. The atrocity lie (such as stories of maltreatment of prisoners).
15. Generalization/extrapolation of a single instance of the enemy's cruelty into a "prevailing habit."
16. The acceptance of human testimony as conclusive without evidence.
17. "Pure romance." Lies and exaggerations told by allied soldiers to their civilian social circle.
18. Subtly misleading evasions, concealments, and half-truths from the government.
19. Official secrecy which must necessarily mislead the public. For example, secret treaties which conceal the intent of the government in disturbing another nation and infringing on their territory.
20. Sham official indignation depending on popular indignation, "a form of falsehood sometimes resorted to in an unguarded moment and subsequently regretted."
21. Illustrated propaganda that misrepresents the enemy.
22. Personal accusations and false charges against persons who refuse to adopt the orthodox attitude towards war.
23. Lying recriminations between nations. In other words, a back-and-forth false accusations between countries.
24. Other varieties of lie not categorized here.