Few people now know Baltasar Gracian, who was a Jesuit priest in the 17th century Spain. His most famous book – The Art of Worldly Wisdom, also known as the Pocket Oracle – became a classic. Friedrich Nietzsche praised this book by saying that “Europe has never produced anything finer or more complicated in matters of moral subtlety.”
Although the Pocket Oracle covers many things, Baltasar Gracian’s influence advice is especially useful. Of course, Gracian does not use the modern terminology, but he covers many of the same things that modern experts cover under the well-known rubrics (such as Cialdini’s weapons of influence – scarcity, social proof, liking, reciprocity, and so on). For example, his point on importance of being first captures the modern marketing concept of positioning (see below 63).
Below you’ll find several of his passages (numbers in brackets refer to his original aphorism numbers). If you want more, I recommend Christopher Maurer’s translation, which is a modern translation and much more readable (I could not reproduce it here because it is copyrighted).
- Keep Matters for a Time in Suspense  Admiration at their novelty heightens the value of your achievements. It is both useless and insipid to play with the cards on the table. If you do not declare yourself immediately, you arouse expectation, especially when the importance of your position makes you the object of general attention. Mix a little mystery with everything, and the very mystery arouses veneration. And when you explain, be not too explicit, just as you do not expose your inmost thoughts in ordinary intercourse.
- Never Exaggerate 
It is an important object of attention not to talk in superlatives, so as neither to offend against truth nor to give a mean idea of one’s understanding. Exaggeration is a prodigality of the judgment which shows the narrowness of one’s knowledge or one’s taste. Praise arouses lively curiosity, begets desire, and if afterwards the value does not correspond to the price, as generally happens, expectation revolts against deception, and revenges itself by underestimating the thing recommended and the person recommending. A prudent man goes more cautiously to work, and prefers to err by omission than by commission. Extraordinary things are rare, therefore moderate ordinary valuation. Exaggeration is a branch of lying, and you lose by it the credit of good taste, which is much, and of good sense, which is more.
- To be the First of the Kind is an Excellence 
and to be eminent in it as well, a double one. To have the first move is a great advantage when the players are equal. Many a’ man would have been a veritable Phoenix if he had been the first of the sort. Those who come first are the heirs of Fame; the others get only a younger brother’s allowance: whatever they do, they cannot persuade the world they are anything more than parrots. The skill of prodigies may find a new path to eminence, but prudence accompanies them all the way. By the novelty of their enterprises sages write their names in the golden book of heroes. Some prefer to be first in things of minor import than second in greater exploits.
- Be all Things to all Men 
A discreet Proteus, learned with the learned, saintly with the sainted. It is the great art to gain every one’s suffrages; their goodwill gains general agreement. Notice men’s moods and adapt yourself to each, genial or serious as the case may be. Follow their lead, glossing over the changes as cunningly as possible. This is an indispensable art for dependent persons. But this savoir faire calls for great cleverness. He only will find no difficulty who has a universal genius in his knowledge and universal ingenuity in his wit.
- Do not play Manille 
Be extraordinary in your excellence, if you like, but be ordinary in your display of it. The more light a torch gives, the more it burns away and the nearer ‘tis to going out. Show yourself less and you will be rewarded by being esteemed more.
- Don’t be a Bore 
The man of one business or of one topic is to be heavy. Brevity flatters and does better business; it gains by courtesy what it loses by curtness. Good things, when short, are twice as good. The quintessence of the matter is more effective than a whole farrago of details.
- Never from Obstinacy take the Wrong Side because your Opponent has anticipated you in taking the Right One 
You begin a fight already beaten and must soon take the flight in disgrace. With bad weapons one can never win. It was astute in the opponent to seize the better side first: it would be a folly to come lagging after with the worst. Such obstinacy is more dangerous in actions than in words, for action encounters more risk than talk. ‘Tis the common failing of the obstinate that they lose the true by contradicting it, and the useful by quarreling with it. The sage never places himself on the side of passion, but espouses the cause of right, either discovering it first or improving it later. If the enemy is a fool, he will in such a case turn round to follow the opposite and worse way. Thus the only way to drive him from the better course it to take it yourself, for his folly will cause him to desert it, and his obstinacy be punished for so doing.
- Know How to Get Your Price for Things 
Their intrinsic value is not sufficient; for all do not bite at the kernel or look into the interior. Most go with the crowd, and go because they see others go. It is a great stroke of art to bring things into repute; at times by praising them, for praise arouses desire; at times by giving them a striking name, which is very useful for putting things at a premium, provided it is done without affectation. Again, it is generally an inducement to profess to supply only connoisseurs, for all think themselves such, and if not, the sense of want arouses the desire. Never call things easy or common: that makes them depreciated rather than made accessible. All rush after the unusual, which is more appetising both for the taste and for the intelligence.
- Keep to Yourself the final Touches of Your Art  This is a maxim of the great masters who pride themselves on this subtlety in teaching their pupils: one must always remain superior, remain master. One must teach an art artfully. The source of knowledge need not be pointed out no more than that of giving. By this means a man preserves the respect and the dependence of others. In amusing and teaching you must keep to the rule: keep up expectation and advance in perfection. To keep a reserve is a great rule for life and for success, especially for those in high place.