The book presents an advanced introduction to PIG. Its a book by an insider for insiders and not an introduction to PIG itself. You may end up producing code to run through some data, but may not necessarily gain any understanding.
The book reads like a blog. Beyond spell check, it has no editorial oversight whatsover. the content order is adhoc it goes from one topic to another without any apparent continuity. for example, right after a cursory introduction to Map Reduce and PIG, the discussion goes into an arcane details of commandline and flag settings without any context.
the book covers a whole lot of concepts, but the introduction of these concepts itself is weak. For example, projections are introduced as something PIG has in common with SQL.
book itself is -2 stars. -1 for amazon's kindle & oreilly. the publishing quality in this book is horrible. the code fonts smaller than main text, uneven spacing etc. default settings on freely available web publishing softwares produces better content than what amazon and orielly have produced here.