A curious attribute of the Scala programming language is that it expends a lot of expressive power in order to make the life of casual programmers simpler. For instance, Scala provides sophisticated type parametrization and traits so that more advanced programmers can design libraries which are at the same time general and easy to use.

Casual users can profit from these libraries long before they discover the full power of Scala's abstraction constructs. The language design avoids the temptation of simply defining some handy primitives in the syntax, even if these primitives would be useful many times to many users. Instead of fixed primitives, the language design tries very hard to provide general construction principles, with which users can then define their own fundamental constructs, at no loss in syntactic convenience. This idea ranges from simple things, such as being able to define your own numeric data types, to full-blown domain-specific APIs such as Scala's support for concurrent actors.

There is hardly a better example of this approach than David Pollak's Lift Web Framework for Scala. It leverages the full expressive power of Scala to provide a framework that's at the same time simple to use, powerful, and secure. David has been one of the earliest adopters of Scala. He has become a crystallization point for many important developments in the Scala community. He fostered the vibrant Lift community, organized the first Scala Lift Off conference in 2008, and promoted the adoption of Scala in many important industrial applications.

His experience puts him in a unique position to explain the language thoroughly and competently. At the same time, David is a great communicator, and he has always the needs of beginners to the language in mind. This book shows these two traits of his very well.

Written by an expert user of the language, it puts the focus on what's important for a beginner.

It moves you swiftly from simple examples to more complete applications, explaining both language and core libraries. It manages to show that Scala is, fundamentally, a pretty simple language to pick up, and at the same time a language with few limits if you want to progress.

I hope you'll enjoy reading it as much as I did.

Martin Odersky

EPFL

Designer of Scala