Suppose you're off on a secluded island, holidays that is, with no wifi around, no dial-up available and no satellite dish/phone to try to connect to the WWW. What do you use then to gather new knowledge and experiences? Besides your partner during night-long day-long discovering of your potential of course, the answer would probably be books or experiments. Well, this small book serves its purpose of, being a book and a compilation of wikipedia articles, offering you some one book shows all introduction to most of the well-known class-based languages. So if stranded on that island you find you need to rewrite a class in a language you don't know already you can use this book as it covers this short time introduction between those you already must have mastered and those you'd like to easily learn without painfull and boring semester-long courses. Sure, you won't become the grandmaster of any of these languages just by reading this book, but to simply comprehend the basic constructions and how to write them in so many alnguages would be a great kickstart to using either as you see fit. It's also good for total newcomers, as most constructs and basic operators are discussed enough for those without prior background to get into grips with class-based programming. However, if you've got an Internet access you might rather consider using online always up-to-date version of the articles devoted to the language you need to learn or simply search for a short and comprehensive bible-style web course/compendium devoted to a certain language of your liking. After all, it's quite short, this book, compared to all those bibles and programming guides containing 500+ pages each, but do not mistake it - this book is solely for presenting a compilation of articles on quite a few languages and should be used as an easy way to fluently learn how the basics are done in more than 1 language. Programmers, you know, need to be polyglots more often than translators do ;) And you're helping the wikipedia foundation by buying this short (re)introduction to those languages used by many.