Not enough to buy it myself although will probably read some excerpts which I imagine will be published by the tabloids.
There is clearly deep rooted resentment that he holds which honestly, he is entitled to. It's essentially akin to favouritism, as he's denied an opportunity in favour of his older brother (I am fully aware that nothing can be done about this).
I do think though his level of continued resentment is unhealthy. At some point, the situation is what it is and carrying it as the constant chip on your shoulder is probably exhausting.
I do feel there are inconsistencies in his words and his actions though. The stories about him not really knowing what therapy is until recently when he set up Heads Together with William and Catherine and he did say his brother was the one to say he should speak to someone. Perhaps it's a play on words as we don't call it therapy here, but counselling? So perhaps true but also misleading.
All in all, I think it's a shame what has happened. I think it's hard to be in someone's shadow and can see why resentment grows. He could have been brilliant in the royal family and taken a role like Princess Anne, but I honestly think he feels he deserves the throne. Irrespective of their birth order (if we could choose a monarch) I would honestly say William is the better choice as he comes across as more calm and controlled but that's besides the point.
I don't know. I just don't think it's healthy to constantly air your grievances to the world. That would be my opinion if the person in question is a Prince or Joe Bloggs from down the road.