I enjoyed this book. It gave a very good overview of all the Swedish kings/monarchs from the loosely collected beginnings to the Sweden that is today.
The first listings were without a doubt quite confusing at times; he was married to her, who was his mothers' cousin married with her uncles..... the intermarriage seemed quite popular (!). I also learned some interesting facts that I did not previously know about. For example, that Swedens' royals were relatives to the russian 'tsar'-family through Peter III. And also that quite a few female royals went to visit/live in Rome to become quite influential abroad.
One thing that you learn quite quickly though - is that being a king...is best done as an only-child. (at least in the early centuries)