Certain books make thinking easier, as having a good framework gives a lovely skeleton to whatever flesh you would like to add to your very own thought golem.
Here's a few of my favourites.
Masanobu Fukuoka - 1978 - One Straw Revolution
It's a gardening manual, a philosophy book, and a biography all wrapped into one, and highlights the importance of letting evolved systems get on with their job, and not letting cleverness get in the way of wisdom.
Robert Anton Wilson - 1990 - Quantum Psychology
Another philosophical book on what we can say about the world around us. Written in e-prime, which can be defined as English without "is".
Lao Tzu - 6th Century BCE - Tao Te Ching
There are many translations, but this one will do for now. Discusses ineffability, impermanence, the nature of change, and all sorts of other goodness.
The Green Gap
In the Cold War, we feared a Missile Gap was a strategic weakness. Nowadays, we must awaken to the fact that the Green Gap is true strategic weakness: the nations whose economies will thrive in the coming years will not be those with the biggest factories, but those with the most sustainable, efficient, and ecological markets. What we require is a Strategic "Green Reserve" of ecological design to weather the coming changes that both climate and resource scarcity will force on the international economy.