Investment reputations, runs a Wall Street saw, are like virginity: They can be preserved but not restored. Sobel (Trammell Crow, Master Builder, 1989, etc., etc.; Business History/Hofstra Univ.) does nothing to disprove this adage in his drab authorized chronicle of the banking firm of Dillon, Read. To be fair, Sobel would have to be an alchemist to drum up much interest in a tradition-bound firm better known for the men it lost to Washington (e.g., James Forrestal and Paul Nitze) than for any signal achievements in investment or merchant banking. Be that as it may, Dillon, Read's antecedents, he explains, date back to 1832. Though respected and consistently profitable, these predecessor enterprises were not, as Sobel makes clear, major forces in American, let alone international, finance. With canny Clarence Dillon at the helm during the Roaring Twenties, however, the firm attracted enough attention apparently to last it for a lifetime. At any rate, Dillon, Read became one of Wall Street's most conservative operations during the Depression and remained so for years thereafter. While rivals converted themselves into financial-services supermarkets, the low-profile House of Dillon, Read clung doggedly to so-called relationship banking. This policy gained the closely held firm a secure niche in the volatile environment that marked the post-WW II era, but Dillon, Read never really capitalized on its opportunities. Acquired and quickly divested by Bechtel Group during the merger mania of the early 1980's, Dillon, Read is doing business today as a wholly owned subsidiary of Travelers Corp. A dreary, frequently fawning recitation of interest mainly to members of the principals' immediate families or their close friends.