I wish I could write "real gem you should read", but I can't -- after reading it from cover to cover I have to admit I wasn't able to read all text, and because of that it is more like "pile of mud with gem in it".
The biggest disappointment of this book is... the author. I bought and I intended to read a book about computer languages. Instead I got ton of "intelligent" remarks how given language syntax looks like Mary Poppins or Mr.Stock. Come on! Is this some kind of fairy tale or pure information for programmers? This fluff is not funny at all, at first I felt embarrassed, but with each such piece more it was nauseating. I don't know -- maybe the author tried very hard to be wit (the results are quite opposite) or maybe it was just easier to make the book thicker instead of spending time providing more details of the languages.
The second, very close to the above, problem is repeating to the death from boredom -- recapping ("so, we've just learned..." and there goes entire section about what was written section before, great if your readers have memory deficits) and constant remarks ("that was easy / that was hard" -- for who, I could ask, because for programmers, it was just code).
It is saddening and disappointing especially, when you realize that in the very introduction the author states "Buy This Book ...if you are a competent programmer who wants to grow.". Now, show me a competent programmer who on one hand knows Lisp, Java, C++, and on the other needs sweeteners like this one "the syntax is logical (...) just not very convenient. Agent Smith just kicked sand all over my kid nephew, and I think I heard him laugh." Really? REALLY?
For us -- programmers who are driven by pure passion -- programming is fun! We don't need Mary Poppins being Ruby (or vice versa), code is interesting by itself. All authors of computer books (except those introductory, for ~8 years old kids) should get this message into their heads. One can make vivid analogy (sequence ~ centipede) but not cracking juvenile "jokes" every second page!
The above part was objective (I hope) -- subjective complain is the goal and execution of the book. Book can teach, or book can just show. I would prefer just showing the most interesting concept of the languages, because, let's face it, if you try to learn 7 languages at the same time, I doubt you are serious, and if you try to do it only with 1, you just paid too much for the value. However, the author tries to teach by showing -- material is very shallow, and I don't think it makes any sense, especially tasks to do on your own (like finding description of the language in Wikipedia; gee, why I didn't think about it before?).
If you (mentally) take out all the dead parts, the rest is rather thin. And it is pity, because I wanted a "programmer feast".
After all this criticism, you expect probably that I will say "junk, don't buy it". No -- buy it despite this. Unfortunately (sic!) this is a good book (something like "a feast for programmers on a diet"). It will (I think) get you inspired. You will learn despite all mistakes, misleading information (author refers to similarities among languages in chapter order, not in chronological order). You will get some word from the designers of the languages (there are interviews with them in the book, although short). Most importantly you will probably get intrigued, teased. And this is the main value of this book, and also it is one of its kind (I don't know anything better than this book) -- I can say for myself, I was intrigued and excited, especially about Erlang and Clojure. Suffice to say, I already ordered book about Erlang, and I consider buying another for Clojure (I won't order one about Scala, because I already have one). But once again, the excitement is thanks to the languages features, not author's writing skills (however I see and appreciate effort of putting seven languages in single book by one, not seven, author).
If you are ready to explore new ideas, you don't live in (Java?) coffin -- this book is for you. But please don't buy it with high hopes.
I, kind of, wait for the second edition. Only (!) if author removes all the sickening-funny stuff, emphasizes unique features of the languages (Clojure macros description takes about the same place as comparisons in Ruby), and "compress" the same (like filter -- in Scala, Haskell, Clojure). It would be valuable to add Forth and Eiffel, and maybe just one chapter for languages for which their time passed -- I think about COBOL and FORTRAN here. They deserve being mentioned, for the purpose of appreciating where we are now.
But if the author will keep fooling around and pretending he is a kid with lollipop in his mouth... -- forget that I even mentioned 2nd edition. I respect other (professional) programmers and I require respect in return.
NOTE FOR POLISH READERS: my final rating is for original book. I would say that Polish edition is something like 2/5 -- because of trashy paper, lousy translation (translator doesn't know Polish too well), and translating the code (which resulted in translating even keywords from time to time!). But the value is still there, so again, even more unfortunately, but it is still worth buying... well, I'd better not say that considering the steep price (it is almost the same price as English original), but reading, yes.