Succinctness is an underestimated virtue in nonfiction: too many books use a page where a sentence would do. Self-help books and pseudo-motivational books are especially remiss, which is to say those entire books can be reduced to almost nothing. That's not to say that the book is not valuable; instead, I mean to say that a sentence can be even more valuable than a book.
But what could I mean by the "value" of a book? In short, a nonfiction book exists to transmit knowing from writer to reader. This is different from merely presenting facts: as any math student knows, a book can be dense with facts yet leave the reader vacant of knowing. On the opposite extreme we have self-help books that are nearly devoid of facts, but are attempting to transmit a specific knowing to the reader. They threaten, describe, exemplify, and cajole, in an attempt to pass on their knowing. And yet they seem to be typically not very good at it. How many people read a powerful self-help book, feel an epiphany, and believe they have been taught, only to wake up in the morning indifferent again, as if from a dream?
A week after this experience, the reader perhaps remembers the feeling of epiphany with some quantity of embarrassment. Even after such a moving self-help book, why have they fallen again? What can they even remember from the 200 pages consumed so readily? Probably nothing more than a single vague concept. This is the seed of the unifying truth; the kernel of knowing. The entire remainder of the text, so readily devoured, was just a mechanism designed to effectively transmit that knowing. And yet, looking back, it didn't seem to work.
The problem is that the self-help mechanism is rarely effective: often self-help books contain a powerful idea that, if known, could change an outlook completely. But this kind of idea meets a lot of resistance in the mind of the reader. This is completely unsurprising: paradigm shifts are never easily perpetrated. Epiphanies are an illusion. They are excitement mistaken for realization. Instead such a powerful idea takes practice and careful thought to take root and become knowing. Gradual change is the only effective method for self-transformation. For this reason, the book rapidly consumed delivers nothing that you can't get from a single sentence, delivered from authority. It simply plants the seed of change. No matter how much motivational material is packed in, a serious transmission of knowing cannot ensue immediately.
There is another factor in play, hinted at above, which is central to the issue. A successful transmission of knowing is the responsibility of the reader as well as the writer. The reader must accept the knowing. However, this process is very slow. Through patient openness, a reader can slowly internalize the truth they have been told. Our mind's digestion is far slower than our stomach's.
Now the problem is that self-help books and similar texts are not designed for this calm, meditative digestion. Instead they whip the reader into a cognitive frenzy. They try to shock the reader into an ecstatic realization. They promote epiphany. This is not a productive strategy! Instead, consider the humble yet lovingly constructed sentence. It is dense with meaning. It grabs at our imagination. It is concise enough that we can memorize it and refer to it often from within our own mind. How often does a reader reopen a self-help book? Maybe a dozen times at most, and yet the sentence can be turned over a dozen times in an hour.
And so a sentence -- a single cutting thought -- can be more valuable than a book. It is a form that is well-suited to transmission of knowing. It is memorable and so it reminds the reader of the truth, again and again. Let a flood rush down a mountain, and it overruns the land and quickly dissipates, but a small mountain stream slowly wears a new pattern into the rock.
Of course, a sentence can't be published, and many misguided readers in fact seek that epiphenatic sensation, like an addict seeking a high. So the self-help book is perpetuated. But I urge you to carefully think about such books as you read them. Don't discard the book entirely, but seek the true sentence behind the mountain of platitude and anecdote. Find that sentence -- that true idea -- and reflect on it again and again. Patiently let it percolate. Distrust epiphany.