Mr Wills (not his real name) owned an antiquarian bookshop in one of the up-market malls in Rosebank, Johannesburg in the 1980's. He was a quirky, bad-tempered Englishman who made you quake if you set foot in his shop but his books were superlative. One just knew that books this beautiful had to be rare books.

Take for instance the account, with illustrations, of two Dutch explorers in the 17th century, Ensigns Bergh and Schrijver, into the hinterland of what is now South Africa.

To put that in perspective: that was so long ago in human history that the black speakers of Bantu languages had not yet come down the African Continent to South Africa. The Europeans had yet to arrive in force. The region was sparsely populated only by the copper-skinned hunting-and-gathering aborigines, the Khoi and Khoisan.

The explorers kept copious journals that are now kept in the Cape Archives. In 1931 Dr E.E. Mossop wrote a book, based on his translation of these journals, entitled Journals of the Expeditions of the Honourable Ensign Olof Bergh (1682 and 1683) and the Ensign Isaq Schrijver (1689). Today copies of Mossop's book rate as rare pieces of Africana, although they do come on onto the book market from time to time.

I remember Mr Wills showing me this book but not allowing me to touch it. It was a rare book, he explained. And so the idea of a rare book was formed in my mind. "Hand-scribed Byzantine tomes are rare. Gutenberg Press books are rare. Self-published Victorian tomes are rare," I thought. I was confident that I knew what a rare book was when we started our bookshop deep in the country, quite near where Schrijver penetrated the mountains for the first time.

Then Mr Besant (not his real name) came asking for a book called A Colossus of Roads by Pat Storrar and Gnther Komnick. It was published in 1984 by Murray & Roberts, a South African construction firm, and concrete firm Concor. The subject of the book is the road passes built through the Great Rift Mountains swathing the eastern and southern sections of the country by one intrepid visionary called Thomas Charles John Bain (1830-1893). His road works still exist in all their daring glory. His endeavours resonate strongly with the travels of Bergh and Schrijver. Whereas the earlier travelers clambered over mountains to explore the interior, Thomas Bain built lasting thoroughfares through mountain passes hacked into the mountainsides, living in remote areas to complete his work.

Mr Besant had been searching for this book for a long time. I assured him that it would not be difficult to find. I would put out the word to the SA Bookdealers Association (SABDA) members and search through the aBillionbooks booksites, I told him to keep his mobile switched on. It would take no more than an hour to locate, I said. I believed that sincerely. My parents were friends with Pat Storrar. I own a signed copy of The Colossus of Roads. How hard could it be to find?

Well, five months later I called Mr Besant's mobile with the good news that I had finally located a copy. "I thought you said it wouldn't take long," he complained. "Well, it is a hard-to-find book," I said firmly. Why didn't I call it a rare book? Something told me it would be sacrilege to place this book, as interesting as it is, alongside books as special and rare as the rare piece of Africana in Mr Wills's shop.

Some semantic significance is attached to word "rare" for us all. "Hard-to-find" apparently means a more recent book that was under-published in error or so popular that no one wants to place their copies in the secondhand market. "Rare" apparently means a book over a hundred years old for which one feels an intuitive veneration.

The difference is spurious, really, now that online bookstores are bringing elusive and obscure books within reach of everyone. Now as a matter of principle I mix the two terms freely and use them interchangeably. True, it is hard to find a rare book. But wouldn't you expect it to be? And hard-to-find books are rare books, even on the internet. That's why they are hard-to-find.

Think about it and decide for yourself.

Copyright 2006 Justine Eaglestone