Born Phyllis Gross in 1909, she was more or less abandoned by her parents at the age of 14, and went to France to teach English at a girls school at Fecamp. With French as her second language she went on to study at the Sorbonne in Paris. She had almost no money, so slept on the streets under newspapers and dried her smalls on radiators in the libraries while she studied.
Earning a meagre living by painting portraits and writing articles for various magazines and newspapers, she returned to England after a few years and in 1926 met and married Richard Pearsall. The marriage lasted for about eight years, during which time she had established a reputation for her writing and for her etchings and painting.
But all of this was interrupted when Pearsall's father, Alexander Gross, wrote to ask her to publish in England a map of the world produced by his map company in the United States. He had emigrated some years earlier after losing the map company he had originally established in Fleet Street. Reluctantly she agreed, and had to learn all the technical jargon involved in reproduction and printing before setting about selling direct to the customer.
It was on one of these selling expeditions that she got lost because of the out-of-date London street map she was using. This was the beginning of her idea of how useful an up-to-date map would be - a map that all could use for business and pleasure.
So in the mid-1930s the A/Z (as it was originally called) was conceived, and during the gestation period Pearsall walked some 23,000 streets of London, collecting street names, house numbers along main roads, bus and tram routes, stations, buildings, museums, palaces etc, in addition compiling the street index in alphabetical order.
Finally after years of intensive labour, rising at 5am and walking for 18 hours a day, the London A-Z was born in 1936. It was researched, printed and distributed by Phyllis Pearsall alone, and drawn up by her father's best map draughtsman, James Duncan.
It had a short pre-war life as all maps at a larger scale than 1in-1 mile could no longer be published after the outbreak of war in 1939. Pearsall became a civil servant at the Ministry of Information; in order to keep her draughtsmen occupied she published war maps of the various battle fronts. After the war regulations were relaxed and street maps and atlases were once again allowed to be published.
I first met her in 1948, and in 1950 joined Geographers' Map Co Ltd, as it was then known - the underlining was to distinguish it from Geographia, the company Pearsall's father had founded before he went to America.
Maps at that time were all hand-drawn on tracing-paper with nib and ruling pen and ink, a skill acquired after a five-year apprenticeship and years of practice, and it was this craft which intrigued Pearsall as an artist.
An accomplished draughtsman herself, she was unable to draw maps, but one has only to see her drawing of the Waterloo Bridge under construction, which she drew from the top of the then Shot Tower (now demolished), to appreciate her great perspective and skill; the original now resides in the Museum of London.
Since our meeting in 1948 Phyllis Pearsall had been badly injured in an air crash in Surrey. A partial recovery many months later saw her return to the office where neglect by the then managers had led to a downturn in the company's affairs. The steps she took enabled it to recover slowly, but the effort affected her frail health and once again she had to have a long period of complete rest.
When she came back she was so weak that it was not unusual for us to carry her up the stairs, so that she could see and discuss how work was progressing in the drawing office.
At this time the general office and the drawing office were in different buildings and it was at Phyllis Pearsall's instigation that an office capable of housing both together was found in Gray's Inn Road.
It was then that we were able to see her more frequently and began to appreciate her care and involvement not just with the business, but with each individual who worked there, whom she considered part of her family. Those days it was a very small family, consisting of three draughtsmen, six in the general office, two representatives, two in the shop and one in the stores.
New publications were slow to materialise as a first-class draughtsman was only expected to be able to letter ten names per hour, but inspired by Pearsall new projects (such as coloured Premier Street Maps of Birmingham, Manchester, Glasgow, Leeds, Bradford in the early 1950s) were undertaken and new personnel recruited. The first A-Z street atlas of Birmingham appeared in the late 1950s. In 1964 the boundaries of Greater London were expanded which led in time to a new Master Atlas of Greater London.
Back on top form, she kept a watchful eye on production and finance and was excited but cautious when a new map was about to be published: "We can easily sell it to ourselves, now we have to sell it to the public," she would say.
Early in 1962 ill-health struck again, and the company was brought to the brink of a financial crisis thanks to mismanagement, in spite of the hard work and loyalty of the rest of the staff. From Pearsall's sick bed she began to have suspicions that all was not well. Yet again her astute foresight and awareness of danger saved the company, but the drama took its toll, and after leaving hospital she found rest and recuperation at Backsetown in Henfield, founded by Dr Wilberforce, where women in business could relax, have good food and be looked after while they recharged their batteries.
In October 1962 the company moved to Sevenoaks, and it was here that Pearsall started to think about the vulnerability of those she cared for in the event of her death. A new management team gave her some comfort and trust as their ideals were the same as hers and she felt able to hand over the reins to a degree, which allowed her to enjoy her return to painting and writing - always ready to drop everything should the business demand. Amongst her books was From Bedsitter to Household Name (1990), the story of A-Z maps.
When the company joined the Small Business Association, Pearsall, with her command of European languages, often travelled abroad to discuss the role of small businesses.
In 1966, sacrificing any thought of personal security, she founded a unique trust for the benefit of the employees and joined in the parnership where she was loved and respected.
The harder business world of today leads us to remember her words, of which she was a master: "How can such fools as us be accepted in business", "You must enjoy the challenge, make it fun and do it", and the prime one for understanding accounts: "Cross off the noughts - it makes it easier".
Phyllis Isobel Gross, artist, writer and publisher: born 25 September 1906; FRGS 1936; MBE 1989; married 1926 Richard Pearsall (marriage dissolved 1938); died Shoreham-by-Sea, Sussex 28 August 1996.