Life is full of things that promise so much but end up taking more than they give. Just like saltwater looks just like drinking water, but if you drink it you will only end up more thirsty until it kills you. Steve Hoppe takes that metaphor and applies it very helpfully to a whole bunch of things in life that end up taking from us, things like money, sex, control, works, etc.
It was also really helpful how Steve encouraged us to find balance in all these things. What we tend to do is react to something unhelpful by taking an opposing extreme position that is also unhelpful (e.g. my parents were too overbearing and I don't want to be like them, so I'll just be completely hands off with my parenting). But the answer is not to react by going to the opposite extreme but to recognise the good while dispensing with the bad, i.e. just throw the bathwater out, not the baby with it, and Steve helpfully led us to a sensible balance in all the areas he addressed.
I also found it very relatable by the way we were introduced to a number of people along the way that you could truly picture in your mind who were living in unhelpful extremes in the areas which were covered.
Overall, I would recommend this book to anyone. Whether you're a Christian or not and you just can't find true satisfaction in life, I'd recommend you read this book to find out why you're not finding it and how you can. It is also helpful for all Christians, whether new in the faith or more mature in the faith, as it will help you examine your life and think through ways your life is out of balance and help you return from the extremes of worshipping the things God has made as if they're gods or throwing them away as if they're garbage, but helping us to remember they are all gifts from him, to be used for his glory.