A LEAKING fountain pen changed the course of writing history. In 1883, Lewis Edson Waterman, an insurance broker, lost a contract after his fountain pen leaked over the document his client was about to sign. At that point, he decided to invent a leak-proof pen and it is on his original design that today's fountain pens are based. He gave up selling insurance, and went on to perfect this most often used of all executive accessories. The latest addition to the collection is named after its founder. The Edson features a transparent blue case overlaid with gold. To complement this pen, there is the matching ballpoint, which mirrors the intrinsic qualities of its mate. Like the fountain pen, the clip of the ballpoint bears a personal number. No executive would dream of signing on the dotted line with a leaky old plastic ballpoint. Yet many can only dream of signing with the $440,000 Cartier Pasha pen, created from solid gold and set with diamonds. The jewelled cap encases a hidden nib of solid gold. It is certainly an impressive pen to scribble a memo to the secretary with. For a few thousand dollars less - but no less prestige - the deal can be sealed with a sapphire and diamond set pen. Each is available by special order from Cartier. A brother pen is the Cougar. This superb writing instrument is highlighted by gold and silver features. Its cap is adorned with an onyx cabochon and the body is encircled with the Cartier signature, three gold rings - the jeweller's trademark. The ultimate in luxury accessories is available as a ballpoint or fountain pen. Another pen the executive would not want to leave behind on the bank counter is the limited edition Mont Blanc Octavian. The Octavian pays homage in design and title to Gaius Octavius, adopted son and heir of Julius Caesar. The pen is overlaid with a spider's web of sterling silver. Alfred Dunhill's Gemline pens are also an attractive accessory to peek out of the executive pocket, without leaving him too much out of pocket. Prices start at $1,200 for fountain pens, ballpoint pens, propelling pencils and convertible pens. The fountain pen's nib of 14-karat gold is cut from a single sheet and carries an engraved Dunhill logo and scroll. It is made by hand with a blade no thicker than a human hair. The ballpoint pen combines elegance with practicality and offers a choice of fine-medium writing points and long-lasting refills. For the younger executive, Yves Saint Laurent has the Boetie pen in vibrant lapis lazuli blue or black. The lacquered range adds a touch of class to a pen collection for about $700. To complement these fine pens, Cartier has the Lapis Lazuli and Silver lines of desk accessories. The Lapis Lazuli collection includes a range of items, and each features the Cartier godrons and lapis lazuli cabochons. The Silver line includes a pen holder, a magnifying paperweight, an ashtray, a round box and a picture frame.