I seem to have entirely given up on paper books now (that is as far as programming books go) and trust either
perldoc or the HTML-equivalent in the Activestate package.
CountZero
A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James
