The code listed below listing 7.3 behaves differently than the book
states:
  scala> def greet() {println("hi")}
  greet: ()Unit

  scala> greet() == ()
  <console>:9: warning: comparing values of types Unit and Unit using
`==' will always yield true
              greet() == ()
                      ^
  hi
  res0: Boolean = true

Book doesn't mention the warning until the next, "Java style" listing on
the next page (163-pdf).

Executing the code in Listing 7.9 with scala 2.9.0.1 gives the following
error:

error: value trimmed is not a member of List[String]
possible cause: maybe a semicolon is missing before `value trimmed'?
    trimmed = line.trim
    ^
one error found

Adding a semicolon as suggested, i.e.:

  line <- fileLines(file);

fixes the problem

The first line:
"the last expression of the block"
should be
"the first expression of the block"

Listing 7.16 does not give the same result as the Java example it is
supposed to "transliterate".  The counter variable i is incremented one
more time than in the Java example because of the lack of a break
statement.

The word "is" is missing in the following sentence:

"Here an example how this library-supplied break method could be applied:"

There is a grammatical error in the following sentence.

"Class Breaks in package scala.util.control
offers a break method, which can be used to exit the an enclosing block
that’s marked with breakable."

The phrase "exit the an enclosing block" has two consecutive articles.