This book is a generally fascinating (mostly as it sets out a new way of thinking about some perennial problems based on the notion of scarcity) - but also occasionally mundane (mostly in the later sections dealing with policy solutions to those problems).
The focus of the book derives from a central insight: that maybe all forms of scarcity have something in common (scarcity of money, scarcity of time, scarcity of companionship) and the - apparently strongly evidenced not to say proven - related thought that there is a psychology of scarcity. Scarcity itself, that is to say, gives rise to certain behaviours.
Those behaviours are focussing (useful: we act in a more focussed way with deadlines and better externally imposed harsh deadlines than ones we give ourselves); but on the other hand we suffer from tunnelling (we solve the problem in hand, but often just simply neglect what falls outside the current frame of reference. Then again, under conditions of scarcity, our willpower is impaired and so is our free-floating attention and intellectual ability (our bandwidth is less). Then again, we will borrow from the future to solve the problems of the present - time or cash. And under laboratory conditions, it's better just simply not to be able to borrow (time) at all when completing tasks where time is scarce.
We get very good at trade-offs under scarcity (as we would when packing a small but not a large suitcase). But our attitude towards money is just fundamentally different if we have 'slack' - we may be less economically rational (less likely to sweat the small stuff on a big money transaction) but we are in a position to absorb shocks to the system (financial or time wise) and view the small stuff in itself in a different light. (There's nothing against which we are trading it off.)
The book is a bit less revelatory when it turns to suggesting remedies for the problems of scarcity: good design (courses on money management for those taking out micro loans that actually help them); identifying and managing scarcity in organisations (hospital beds split between elective and emergency care; maxing out the use of restaurant tables), and designing out problems in our everyday lives (being interrupted so our appointments don't run on; hiring good assistants who can provide extra bandwidth; just paying for things automatically so they don't occupy bandwidth; automatic filling out of forms for the poor to avoid the use of bandwidth on transactions).
Still, overall, an interesting new take on some perennial problems.