> Book as baby probably traces back, through many intermediate links, to 
> Plato's *Symposium*, don't you think?

And probably Plato was using some other person's hackneyed idea. Here is 
Aristophanes' Chorus from The Clouds, from 423 BC. His plays and their 
manuscripts are his children, here illegitimate children exposed and left 
for other mothers to raise:

CHORUS
Spectators, I will freely declare to you the truth, by Bacchus, who 
nurtured me! So may I conquer, and be accounted skillful, as that, deeming 
you to be clever spectators, and this to be the cleverest of my comedies, 
I thought proper to let you first taste that comedy, which gave me the 
greatest labour. And then I retired from the contest defeated by vulgar 
fellows, though I did not deserve it. These things, therefore, I object to 
you, a learned audience, for whose sake I was expending this labour. But 
not even thus will I ever willingly desert the discerning portion of you. 
For since what time my Modest Man and my Rake were very highly praised 
here by an audience, with whom it is a pleasure even to hold converse, and 
I (for I was still a virgin, and it was not lawful for me as yet to have 
children) exposed my offspring, and another girl took it up, and owned it, 
and you generously reared and educated it, from this time I have had sure 
pledges of your good will toward me. Now, therefore, like that well-known 
Electra, has this comedy come seeking, if haply it meet with an audience 
so clever, for it will recognize, if it should see, the lock of its 
brother. But see how modest she is by nature, who, in the first place, has 
come, having stitched to her no leathern phallus hanging down, red at the 
top, and thick, to set the boys a laughing; nor yet jeered the 
bald-headed, nor danced the cordax; nor does the old man who speaks the 
verses beat the person near him with his staff, keeping out of sight 
wretched ribaldry; nor has she rushed in with torches, nor does she shout 
iou, iou; but has come relying on herself and her verses. And I, although 
so excellent a poet, do not give myself airs, nor do I seek to deceive you 
by twice and thrice bringing forward the same pieces; but I am always 
clever at introducing new fashions, not at all resembling each other, and 
all of them clever; who struck Cleon in the belly when at the height of 
his power, and could not bear to attack him afterward when he was down. 
But these scribblers, when once Hyperbolus has given them a handle, keep 
ever trampling on this wretched man and his mother. Eupolis, indeed, first 
of all craftily introduced his Maricas, having basely, base fellow, 
spoiled by altering my play of the Knights, having added to it, for the 
sake of the cordax, a drunken old woman, whom Phrynichus long ago 
poetized, whom the whale was for devouring. Then again Hermippus made 
verses on Hyperbolus; and now all others press hard upon Hyperbolus, 
imitating my simile of the eels. Whoever, therefore, laughs at these, let 
him not take pleasure in my attempts; but if you are delighted with me and 
my inventions, in times to come you will seem to be wise."
(Aristophanes, THE CLOUDS, transl. Hickie, ll, 518-62)


az