Sadly though, so many fail to heed that maxim and among those who seem to think the rest of us should benefit from their written words (of wisdom?) are French politicians.
A couple of years ago France Inter dedicated its weekly one-hour programme "Le Grand Bain" to the very question as to why so many French politicians felt the need to write and publish.
The conclusion being that while some had written something worthwhile reading and a certain talent in expressing themselves, the vast majority of them were best served leaving literature, in all its forms, to others and concentrating on what they supposedly did best.
Of course an inflated ego (which politicians must have believing, presumably, that they know best how to serve their fellow citizens in office and determine what's in the interests of the country) must play a part.
But the bottom line of (most) publishing (houses) is surely also to make money - which opens up perhaps the equally perplexing question as to how come so many French politicians manage to find an editor... because so many "œuvres" (inverted commas entirely intentional) are far from being profitable.
Quite the contrary.
Take, for example, the most recent offering from Christine Boutin, "Qu'est-ce que le parti chrétien-démocrate ?".
You remember her, surely.
Boutin served as housing minister for a couple of years during Nicolas Sarkozy's presidency before being unceremoniously sacked.
She was also at the forefront of the demonstrations against same-sex marriage in 2013, continuing her long campaign for Christian values (aka "family values" in her parlance) and boring most of us silly with her frequently ignorant and equally ill-judged remarks.
In 2014, for example, Boutin shared her views on homosexuality with the quarterly political magazine "Charles" describing it as "an abomination".
Ah well. You can read all about that here - old news - but it'll stick around to haunt her (or more likely the rest of us) for quite a while.
Back to that book "Qu'est-ce que le parti chrétien-démocrate ?" ("What is the Christian Democrat party") her 128-page 2010 follow-up to her 2009 book "Chrétiens : de l'audace pour la politique".
Guess how many copies, according to GQ magazine, Boutin has managed to sell.
|Christine Boutin's "Qu'est-ce que le Parti chrétien-démocrate ?" (screenshot Amazon.fr)|
Pause for thought.
It pretty much tells the whole story, don't you think.
Of course Boutin isn't alone among politicians who fail to attract readers.
The current finance minister, Michel Sapin sold 346 copies in three weeks of his diary as employment minister "L'écume et l'océan , Chronique d'un ministre du travail" (clearly few were interested).
The president of the national assembly, Claude Bartolone, fared no better with his "Je ne me tairai plus" ("I'm not going to remain silent any longer") which was bought by only 268 people in two weeks.
And the former environment minister Delphine Batho only managed to shift 715 copies of her book "L'Insoumise".
At the other end of the scale - and perhaps providing a lesson (if not literary, at least a commercial one) was that political potboiler from France's former first lady Valérie Trierweiler.
Her "Merci pour ce moment" has so far sold more than 600,000 (and counting) copies, proving that...well, a tell-all political tale about her relationship with the French president, François Hollande, really might have been a "triumph of self-obsessed raving" but it certainly earned her a bob or two.