Haskell Almanac will be a direct follow-on from Haskell Programming from First Principles focused on intermediate topics and practical needs. A special focus will be on teaching readers to be less dependent on predigested resources to use tools and libraries they didn't write themselves.
If you have not worked through “Haskell Programming from First Principles” yet, do that first! The first ¾ of the Haskell Book is prerequsite for working through the Almanac!