I'd read Wiking's Little Book of Hygge last year, and absolutely loved it; it was one of those right time/right books moments, and I took away a lot of good suggestions.  So when this book's publication was announced, I kept an eye out for it. 

In some ways, The Little Book of Lykke is a more interesting one; it's focused heavily on the research behind happiness both on an individual and cultural level.  There are more studies cited, more graphs, more statistics, and case studies from around the globe about how people and communities have come together to create a better atmosphere for themselves and others.  Wiking includes practical tips for the reader, but I don't think that's the book's strength; I think it serves as food for thought about the larger idea of what makes individuals and communities really happy, and the downstream benefits of being happy.

My only niggle against the book is that the last chapter ends a bit preachy.  This is not entirely the author's fault, as the last chapter, entitled kindness was the chapter with the least amount of available stats and studies, so it was almost entirely anecdotal.  It's really difficult to talk about being kind to others without sounding preachy, I get that.  But it did leave the book ending weaker than it started by just a smidgen.  Overall, a good book for inspiring introspection and an inspiring one in terms of new ideas.