The book is well set out and each chapter covers a different theme / policy area, with key facts, the arguments for leaving and for remaining, as well as a general discussion with examples. There were chapters covering immigration, the EU budget, trade, justice, farming, fishing, defence and foreign aid amongst others. It draws on a number of studies and reports, going into a fair bit of detail. It's not a long book, 300-350 pages, but it is long enough and certainly longer than many of the books about the EU referendum that are springing up.
I thought this was a really good book that covers all the main areas that you'd want it to. What it doesn't do is explain what the EU does or how the various EU institutions work, instead it assumes a certain degree of prior knowledge on the subject. This isn't actually a problem, even if you don't know the ins and outs of the system, you get the gist of how things work. The only area where it becomes a bit of a problem is in the discussion of the "democratic deficit", i.e. the extent to which laws are passed affecting us where we haven't had a say in it. Without a good understanding of the workings of the European Commission, EU Parliament etc it is difficult to judge the argument either way. This is a minor flaw though, and one that is easily rectified if need be with a bit of reading on Wikipedia or similar.
One of the book's main strengths is it's balance, even something close to impartiality. There is plenty in this book for both sides in the referendum argument to be happy with. It is very difficult to work out which side the author favours - some chapters it looks like he's in the Leave camp, others that he's pro-EU. I think though that just shows that some themes and policy areas favour remaining in the EU, others lean more towards us leaving.
Those readers looking for the book to tell them which way to vote will be left disappointed (though there are plenty of biased books that will do that). Instead it leaves you with a lot to think about and allow you to make a more informed judgement which can only be a good thing. I'm giving this a solid 8/10.
A note about versions
This book was written shortly before the 2015 General Election, after David Cameron had announced he'd hold a referendum if the Conservatives won the general election, before the referendum was formally agreed. It therefore doesn't cover David Cameron's recent EU deal. Having just been on Amazon however, it appears that a new version of the book is to be released in the next couple of weeks, which presumably will cover this. So it could be worth waiting for then to buy the book. I don't think it matters too much however, as Cameron's deal doesn't change the key issues.