Today thousands of books, thousands of titles and thousands of copies of each title are published. In antiquity the publishing industry was much smaller, but there is an important book trade first on papyrus and then on parchment or skin.
Well, then as now there were people who exhibited books on the shelves in their homes just for show, books which they had not read, if not they went so far as to state simulated books in the libraries, empty boxes representing the book spine of important books, although according to the words of Seneca, book spines were all that some Romans saw.
Seneca refers to this custom in his "De animi tranquillitate," (On tranquillity of mind), 9, 4
What is the use of having countless books and libraries, whose titles their owners can scarcely read through in a whole lifetime? The learner is, not instructed, but burdened by the mass of them, and it is much better to surrender yourself to a few authors than to wander through many. Forty thousand books were burned\b at Alexandria; let someone else praise this library as the most noble monument to the wealth of kings, as did Titus Livius, who says\c that it was the most distinguished achievement of the good taste and solicitude of kings. There was no "good taste" or "solicitude" about it, but only learned luxury – nay, not even "learned," since they had collected the books, not for the sake of learning, but to make a show, just as many who lack even a child's knowledge of letters use books, not as the tools of learning, but as decorations for the diningroom. Therefore, let just as many books be acquired as are enough, but not for mere show. "It is more respectable," you say, "to squander money on these than on Corinthian bronzes and on pictures." But excess in anything becomes a fault. What excuse have you to offer for a man who seeks to have bookcases of citrus-wood and ivory, who collects the works of unknown or diseredited authors and sits yawning in the midst of so many thousand books, who gets most of his pleasure from the outsides of volumes and their titles? Consequently it is in the houses of the laziest men that you will see a full collection of orations and history with the boxes piled right up to the ceiling; for by now among cold baths and hot baths a library also is equipped as a necessary ornament of a great house. I would readily pardon these men if they were led astray by their excessive zeal for learning. But as it is,these collections of the works of sacred genius with all the portraits that adorn them are bought for show and a decoration of their walls. (Translation by J.W. Basore) .
Studiorum quoque, quae liberalissima impensa est, tamdiu rationem habet quamdiu modum. Quo innumerabiles libros et bibliothecas, quarum dominus uix tota uita indices perlegit? Onerat discentem turba, non instruit, multoque satius est paucis te auctoribus tradere quam errare per multos. 5 Quadraginta milia librorum Alexandriae arserunt. Pulcherrimum regiae opulentiae monumentum alius laudauerit, sicut et Liuius, qui elegantiae regum curaeque egregium id opus ait fuisse. Non fuit elegantia illud aut cura, sed studiosa luxuria, immo ne studiosa quidem, quoniam non in studium, sed in spectaculum comparauerant, sicut plerisque ignaris etiam puerilium litterarum libri non studiorum instrumenta, sed cenationum ornamenta sunt. Paretur itaque librorum quantum satis sit, nihil in apparatum. 6 (Honestius, inquis, huc se impensae quam in Corinthia pictasque tabulas effuderint.) Vitiosum est ubique quod nimium est. Quid habes cur ignoscas homini armaria e citro atque ebore captanti, corpora conquirenti aut ignotorum auctorum aut improbatorum et inter tot milia librorum oscitanti, cui uoluminum suorum frontes maxime placent titulique? 7 Apud desidiosissimos ergo uidebis quicquid orationum historiarumque est, tecto tenus exstructa loculamenta: iam enim, inter balnearia et thermas, bibliotheca quoque ut necessarium domus ornamentum expolitur. Ignoscerem plane, si studiorum nimia cupidine erraretur; nunc ista conquisita, cum imaginibus suis discripta, sacrorum opera ingeniorum in speciem et cultum parietum comparantur.