Only Text Quote
A detective novel should contain no long descriptive passages, no literary dallying with side-issues, no subtly worked-out character analyses, no 'atmospheric' preoccupations. Such matters have no vital place in a record of crime and deduction. They hold up the action and introduce issues irrelevant to the main purpose, which is to state a problem, analyze it, and bring it to a successful conclusion. To be sure, there must be a sufficient descriptiveness and character delineation to give the novel verisimilitude.
