Arriving at the Bodleian Library to meet the head of one of the greatest map departments of the world, I wondered what a map librarian was going to look like. All I had to go on was the image in my head of TV presenter Nicholas Crane, host of BBC's Coast and The Map Man.

Oddly enough Nick Millea proved to be not unlike his better-known namesake - with a boyish smile that made it hard to believe he is 47.

But how do you get to be a map librarian? Nick admitted that geography was his favourite subject at school.

"Yes, there was no contest. I went on to do my degree in geography at Newcastle upon Tyne - they ran an excellent course. It was a good place to study, I still go back to Northumberland for holidays. There is a lot of geography up there! Then I did my post graduate diploma in librarianship back home in Manchester."

Nick was working at the University of Sussex when the Bodleian's map librarian retired and the job became vacant. He jumped at the chance of the job. "I was lucky enough to get it," he said. "My top-of-the-list map job!"

Nick is author of The Gough Map: The Earliest Road Map of Great Britain? published earlier this year. Appropriately enough, Nicholas Crane was the guest of honour at the book's launch party.

What inspired him to write it?

"There were two catalysts,' Nick explained. "The previous reference book about the map had gone out of print and, secondly, the map was digitised in 2004 for the Oxford Digital Library, thanks to a gift from the Andrew W Mellon Foundation. This enabled the reproduction of exceptionally good-quality illustrations for the book."

The Gough Map is named after Richard Gough, an 18th-century antiquary and authority on British topography, who gave the map, along with the rest of his collection, to the Bodleian. The map was revolutionary for its time in that, however basic, it was a geographical image of Britain, rather than a theological one.

Drawn on two pieces of animal hide, the map can be dated to within 11 years, but it is thought to be a copy of an earlier map drawn, possibly, as early as 1280. This map was originally probably one of a number held in different parts of the country but, if so, it is the only one surviving today.

"The Gough Map was a benchmark in map-making in Britain in the 14th century," he added. "At that time the best maps were being drawn, for trading purposes, in the Mediterranean area and were far more sophisticated than anything being produced in Britain."

Nick continued: "The Gough Map book is a marker in the sand. It is a statement of what we know, what we don't know, and what we would like to know. There is so much more out there.

"However, it is a lot of work to produce a book on top of a full-time job running this department."

But what exactly is the defintion of a map?

"It is a two-dimensional representation of space covered with symbols," said Nick.

"In the old days the symbols were obvious. Small houses and churches for example, nowadays you would have to look up a legend to know what the symbol meant.

"Going further back in time before maps were written down' people carried directions in their head, a list or an itinerary.

"The Australian aborigines sang' their maps for thousands of years. If you went walking out into the bush with hardly any landmarks to guide you it was vital you went in the right direction, following a known route, even if you couldn't see it. Timing was crucial, the position of the sun and so on. Words are best remembered sung and the correct singing would give the timing."

Spellings on maps have regional accents,' Nick claimed. "Spelling, as we know, was arbitrary in the Middle Ages but it is emerging that there were local spelling conventions.

"This is one of the things we hope to be studying with Queen's University, Belfast. This will give us far more accurate dating and placing of the Gough Map."

He explained that Queen's is hoping to collaborate on a research project with the Bodleian, using geographical information systems (GIS) which enable maps, such as the Gough Map, to be studied online.

The convention of drawing maps with a North/South orientation came in with the invention of the magnetic compass in the fifteenth century. Maps were a tool of immense power and the map maker would have been a powerful man indeed in that he could determine what went in and, perhaps even more importantly, what was left out. In the late Middle Ages only a handful of educated people would have been able to read a map and make use of it.

Thin Red Lines, Hadrian's Wall and Rivers We make the things that are most important to the map's purpose the biggest on maps,' said Nick. He went on to explain that on a current road map, motorways will appear disproportionately large; on the Gough Map rivers assume that importance. Hadrian's Wall is prominent, as it would indeed have been before stones were taken from it for building purposes. The thin red lines are intriguing and the cause of much discussion amongst experts. Why do they link up some towns and cities and not others? They all have numbers in Roman numerals next to them. Were they simply the distances between places?

Nick explains, at the beginning of the third chapter, that in order to appreciate the importance of the Gough Map you have to understand what kind of maps existed prior to the thirteen hundreds. Earlier maps were of little practical use to travellers but depicted space from an historic and theological point of view. The most famous map of this kind is the Hereford Mappa Mundi, created around 1285 which places Jerusalem at the centre of the world with everything else somewhere round it. East is at the top with the Garden of Eden representing the beginning of time. In many ways the Mappa Mundi is not a map at all. Certainly not as we know maps today.

The Bodleian Library Map Department Strictly speaking,' explained Nick, "it is the Map Section within the Department of Special Collections and Western Manuscripts, but if you access the website, which anyone can, it will come up as Map Room'. So, I don't have to be a reader, hold a card or anything? Is it free to air' as it were?' Yes,' Nick confirmed.

The Bodleian Library Map Department which holds 1.25 million maps, 20,000 atlases and an every growing number of CD-ROMs, digital datasets and cartographic software is, along with the British Library, one of the two biggest map depositories in Britain, far exceeding any others. Both are holders of two of the top ten collections in the world. The map department of the Library of Congress is the biggest in the world,' says Nick, and for me, personally, the Berlin Staatsbibliotek has the most enviable storage system,' Does Nick visit other libraries when on holiday abroad - well, yes he does. Why do the words, busman' and holiday' spring to mind!

The Bodleian Map Department has won many prizes for its website. It led the way in this area and anyone with access to the Internet can use it. It even includes a route finding facility.

The Bodleian and the British Library, as legal deposit libraries, both hold almost complete collections of the Ordnance Survey maps, unlike Ordnance Survey themselves which was bombed during World War II and lost most of its holdings.

Copyright maps from the United Kingdom arrive at the Library constantly; many maps are given to the department; maps are bought if of historic interest, and of course, maps of the rest of the world have to be bought when required. Much purchasing is done according to readers' requests. The USA is particularly generous in the donation of American maps.

Digital mapping for the Educational sector is bought in and is available to current members of the university. This section is constantly growing. At present seven members of staff work in the map department. At one time three posts were sponsored by environmental auditing companies in order to meet their demands on the department.

Finally I asked Nick to name some of his favourite maps of all time: here is his list.

The Oxford Drink Map, produced in 1883 by the Temperance Society was meant to be a political statement, an expose, if you like, of how shockingly many drinking houses there were in Oxford - however it ended up becoming a guide to where to find a drink!

The 1973 town plan of Oxford produced by the Soviet Military - let's just say it is alarmingly thorough!

The Gough Map - of course!

The London Tube Map - it is an icon, not really a map, but very clever and much loved.

The Times Comprehensive Atlas of the World, maps don't get any better than that!

Any map produced by the Swiss national mapping agency (Swisstopo) - they depict mountains so beautifully!

The Sheldon Tapestry Map of Gloucestershire - commissioned by Ralph Sheldon in the 1590s - it is of major cartographical significance, and has recently been acquired by the Bodleian.

I left the Library, and Nick, with an infinitely wider vision of what constitutes a map. I couldn't get out of my head that image of the aborigines singing their routes, passing the information on from generation to generation. And this is where I have to be honest. I am a typical female when it comes to route finding and orienteering. I'm sure there are lots of women out there who are just as good at map reading as their men folk, but I'm afraid I'm one of the ones who gives credence to the old joke that women can't read a map. On a bad day, with the wind in the wrong direction, I am quite capable of getting lost between my house and the supermarket. However, inspired by Nick's tales of the aborigines, I may now have the answer to girl-orienteering. So, if in the near future you see a female driver singing her way to Sainsburys, you'll know it's just me testing out my theory.