Seriously, I have said it before and I shall say it again - this is the one book I have found to be most useful out of all those I have read so far on the topic of bi/multilingualism.
The book takes a fresh approach to the subject matter by providing a summary of what the experts in the field have to say and then asking actual bilingual and multilingual families to talk about their actual experience on the ground.
The real gem for me is the second part of the book which has tonnes of suggested resources and tried and tested ideas to help bi/multilingualism flourish in your family. The author herself is trilingual and has two bilingual daughters, so she has a wealth of personal experience to draw upon.
You can read a free excerpt of the book here or buy a copy for download on Amazon (by clicking here) currently at the seriously low price of £3.82. Also, if you click on the 'Look Inside' icon on the book cover on Amazon, you'll be able to see the chapter list which will give you a good idea of the scope of the book. Chapter 5 covers raising bilingual children in a non-native language :D