It's not a 'bible' of thriftiness. You won't find the answer to every problem in here, but what you will find are a lot of starting places which you can explore further as your need or taste takes you. For instance, there's a section on gardening, with ideas about how you can grow salad and some other crops for family consumption. The attitude is 'look, I did this from scratch and so can you. Here are a few ideas, books, websites and shops which can get you started'. There's inspiration there.
So, what is it then? Well, India Knight takes nine areas – food, clothes, crafts, community, having fun, beauty, holidays, home and money – and looks at buying sensibly. She gives lots of good ideas for how you can cut back, save or even cut out and still live well. There are plenty of resources for further exploration such as websites which you might not have found easily or books. The books are all sensible choices rather than the 'one author scratching another's back' which is so often the case with book recommendations. I can personally vouch for [[The Kitchen Revolution by Rosie Sykes, Polly Russell and Zoe Heron]] which would be a splendid investment for anyone serious about cooking good food from scratch. You might also find [[Hollywood Beauty: Vintage Secrets by Laura Slater]] interesting.
If you're hoping that this book will transform your finances overnight then I'm afraid that it's going to be a disappointment but if you're serious about getting or keeping your finances in order and need a starting point then this could be the best money that you've ever spent. The book is never preachy simply because it's written by someone who has probably been in far worse financial straights than most of us. There's sympathy, understanding and a positive approach to putting everything on a better footing.