THE bookshelves in the conference room of Tweedy, Browne & Company are lined with financial history. Dry securities references, some of them filigreed and bound in cracked brown leather, date back to 1939. These were the books that Howard Browne, a co-founder, consulted when he bought and sold stocks for the likes of Benjamin Graham, the father of value investing and the firm's biggest customer in the 1930's and 1940's.

Later, in the 1960's, Tweedy, Browne brokered for Warren E. Buffett, the sage of Omaha, and sold him his original shares of Berkshire Hathaway Inc., which he now runs.

No doubt about it, Tweedy, Browne's value roots stretch deep. Today, two of Harold Browne's sons, William H., 54, and Christopher H., 52, are among the five managing partners of the firm. There have been some changes -- 70 percent of the firm was sold in October 1997 to Affilliated Managers Group, for $300 million, but the deal had to do with estate planning purposes, not market concerns.

Tweedy, Browne now has $1.5 billion in accounts managed for individual clients; those accounts have returned an annual average of 19.1 percent, net of fees, from 1975, when the company registered with the Securities and Exchange Commission as an investment adviser, through Sept. 30 of this year, according to company reports. That compares with an annual average return of 16.4 percent for the Standard & Poor's 500-stock index over the same period.