Michiel bought a bunch of second hand Ospreys from the Dutch equivalent of eBay. And this one he already had, so I got it from him (it's good to have friends!). It's a quick read, but not necessarily a very worthwhile one.
For me the book was badly organised and confusing. The language is a bit convoluted sometimes, and David Nicolle might have done a better job editing his Swedish (?)co-author.
It already starts with the exposition of the Baltic crusades. This doesn´t go much farther than generalisations about causes and motivations you can find everywhere. Then you get a chronology and a very short introduction about the organisation of the armies, which basically says we don´t know much about it. Strangely, much of this context is stuck on at the end of the book.
Most of the book is about weapons and armour, broken up in four time periods for both the Scandinavians and their Baltic opponents. This leads to fragmentation and repetition, because in every one of these some development in the make of swords must be mentioned, even if it is irrelevant.
The part on strategy and tactics, despite the terrible writing style, offers the best bits of the book. The influence of the terrain and the very small size of the forces involved explain how the campaigns were slow and grinding and stuck to main rivers and siegecraft. And unlike the west, the winter was a season suited to campaigning.
As always, the illustrations by Angus McBride are the real boon. But that won´t save this book. It doesn´t inspire further research, nor does it give you the barest necessities to start a wargame army. It could have done with a couple of examples of important campaigns.