This is quoted from the book. It's a page or so further on.
Laying out text over multiple lines is usually just a convenience to
make your PHP code easier to read, because once it is displayed in a
web page, HTML formatting rules take over and whitespace is suppressed
(but $author is still replaced with the variable’s value). So, for
example, if you load these multiline output examples into a browser
they will not display over several lines, because all browsers treat
newlines just like spaces. However, if you use the browser’s view
source feature, you will find that the newlines are correctly placed,
and the output does appear over several lines.