We have all heard the arguments about how fair/unfair the tax system is. Lansley doesn't go there. Wisely, in my opinion, because most of us have already got fixed ideas about that.
The strength of his book is that it takes a new angle, namely, that inequality stops a free enterprise system from working properly. His target is workability, not morality. He then shows that it isn't new. The same arguments were being made years ago, and it was only when they were heeded that the recovery from previous great depressions began. Lansley doesn't rely on rhetoric, however: he presents plenty of cogently-argued evidence that the same conditions which produced the Great Depression of the 1930s were also visible in the 2000s. What's more, many people saw it and warned what was to come. The politicians put their hands over their ears and refused to listen, like an over-excited child who's been told it's bedtime.
The fact is that if too much wealth is held by the super-rich, they don't do anything productive with it. No one can spend that much on consumables, so they spend it on pushing up the value of van Goghs and on financial speculation. That accumulates even more money, but it doesn't produce anything. The squeeze is on the rest of us. This argument is very similar to that of the Patriotic Millionaires in the USA, who argue that they should be taxed more in order to leave less well-off people more free cash. What creates jobs and new businesses is ordinary people having money to spend. That's what creates demand, and without demand there can be no growth. It remains to be seen whether "quantitative easing" will make any difference, but my hunch is it won't, because the money goes where the money already is, not into demand.
Sounds simple? It is. Everyone should read this book.