The script employed being the prototype of the modern printed text, it will be obvious that a scribe could produce but a few pages at best in a day.

A large work would therefore require the labor of a scribe for many months or even for several years.
We may assume, then, that it would be a very flourishing publisher who could produce a hundred volumes all told per annum; and probably there were not many publishers at any given time, even in the period of Rome's greatest glory, who had anything like this output.
As there was a large number of authors in every generation of the classical period, it follows that most of these authors must have been obliged to content themselves with editions numbering very few copies; and it goes without saying that the greater number of books were never reproduced in what might be called a second edition.

Even books that retained their popularity for several generations would presently fail to arouse sufficient interest to be copied; and in due course such works would pass out of existence altogether.

Doubtless many hundreds of books were thus lost before the close of the classical period, the names of their authors being quite forgotten, or preserved only through a chance reference; and of course the work of elimination went on much more rapidly during the Middle Ages, when the interest in classical literature sank to so low an ebb in the West.

Such collections of references and quotations as the Greek Anthology and the famous anthologies of Stobaeus and Athanasius and Eusebius give us glimpses of a host of writers--more than seven hundred are quoted by Stobaeus--a very large proportion of whom are quite unknown except through these brief excerpts from their lost works.
Quite naturally the scientific works suffered at least as largely as any others in an age given over to ecclesiastical dreamings.