effort, an entire lack of one or more of these principal
elements of Certain Success will cause partial or utter failure in your
life ambition. You will be like a man who tries to open a safe with a
four-combination lock, though he knows only two or three of the numbers.

No one, however well fitted for success elsewhere, can succeed in the
_wrong field_, or in rendering services for which _he_ is not qualified.
Nor is complete success attainable by a man unless he develops the
_best_ that is in him. Even if he brings to the right market his utmost
ability, he may fail miserably by making a _false impression_ that he
is unfitted for the opportunity he wants. Or he may be overlooked
because he does not make the _true_ impression of his fitness.

Evidently, in order to gain a _chance_ to succeed, anyone must first
_sell_ to the fullest advantage the idea that he is _the_ man for the
opportunity already waiting or for the new opening he makes for himself.
Of course he cannot do this _surely_ unless he _knows how_. Therefore
sales knowledge is _universally needed_ to complement the three other
principal elements of the complete secret of certain success.

[Sidenote: Reasons for Failures]

When we try to explain the failure of any man who seems worthy to have
succeeded, we nearly always say, in substance, one of three things about
his case:

"He is a square peg in a round hole;" by which we usually mean he is a
right man in the wrong place.

Or, "He is capable of filling a better position;" a more polite way of
saying that a man has outgrown his present job but has not developed
ability to get a bigger one.

Oftenest, probably, we declare, "He isn't appreciated."

Very rarely is a worthy man's failure in life ascribed to the commonest
cause--_his personal inefficiency in selling_ to the world comprehension
of his especial qualifications for success.

[Sidenote: What Failures Realize]

If a man is a square peg in a round hole, he should realize that his
particular qualities mu