I've got his book on order, as I've heard it's one of the best leadership books out there (although it'll be hard pressed to beat 100 Days by Admiral Woodward). In the mean time, enjoy 10 leadership lessons from William Slim, located here: http://taskandpurpose.com/10-leadership-lessons-one-britains-greatest-soldiers/
1. Ruthlessly enforce standards.
2. Beware of the Bad Idea Fairy.
3. Nothing happens without logistics. And logistics doesn’t happen without logisticians.
4. Every soldier is a rifleman.
5. Planning is everything. And nothing.
6. Give up your best people for the good of the institution.
7. Establish a “battle rhythm.”
8. Commanders are cat wranglers.
9. Keep it short and sweet.
10. “Imitations are rarely masterpieces.”
Follow the link for a longer description of each.