S. S. Van Dine quotes:

There simply must be a corpse in a detective novel,

There simply must be a corpse in a detective novel, and the deader the corpse the better.

It has long been a source of wonder to me why the leading criminological writers--men like Edmund Lester Pearson, H. B. Irving, Filson Young, Canon Brookes, William Bolitho, and Harold Eaton--have not devoted more space to the Greene tragedy; for here, surely, is one of the outstanding murder mysteries of modern times--a case practically unique in the annals of latter-day crime.

Of all the criminal cases in which Philo Vance participated as unofficial investigator, the most sinister, the most bizarre, the seemingly most incomprehensible, and certainly the most terrifying was the one that followed the famous Greene murders.

Only, as long as we're going insane we may as well go the whole way. A mere shred of sanity is of no value.

There are few punishments too severe for a popular novel writer,

But society is ignorant and venomous, devoid of any trace of insight or understanding. It exalts knavery, and worships stupidity. It crucifies the intelligent, and puts the diseased in dungeons.

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.

Giving full rein to one's cynicism as one goes along produces a normal outlet and maintains an emotional equilibrium.