The first part of this book starts with a reasoned crtique of the Bauhaus mantra, form follows function. Start with the word "function" - he effectively takes it apart. Think of a car and its function for example. It can, at different times, demand attention from every girl on the block, it can open its back seat on lover's lane, rush a woman to the maternity ward, or carry kids to the soccer game. What is its 'real' function?
It took me a while to catch the sense that Pye meant to convey. He uses a Zen-like approach of creating new meaning by undermining the old. Beauty, of course, is in the eye of the beholder, but people don't share eyes with each other. It's in each eye uniquely, and has to be defined again by each beholder.
Beauty is also, he argues, a necessity of life and of society. Very often, beauty costs nothing. Any function can be met by an infinite family of forms, even within a rigid framework of requirements. Choosing an agreeable form is not just an option, it's a deep-set human imperative.
This is a philosophical book. It's real point, I think, is that good design must be a personal act - the technical skills can be taught, but the craft must be learned. There is no advice here that you could follow, for example, in making a better chair.
The advice is about how to make yourself a better designer.