(FORTUNE Magazine) – THE HANGOVER from Black Monday's stock market bash has President Reagan's Brady Commission and other would-be exchange regulators resolving to reform. Should the country heed them and adopt new prohibitions on trading? Searching for expert answers, associate editor Rob Norton and reporter Charles Riley spent six weeks sizing up where the markets failed, where they worked, how they've been changed by Black Monday -- and how new trading rules may affect investors and the U.S. economy after the binge. Norton's sober-eyed search took him from the din of the trading pits of the Chicago Mercantile Exchange to the tranquil, ivory-towered aeries of the country's leading market historians and theoreticians. Of his timely analysis, which was edited by Julie Connelly and begins on page 18, Norton concludes, ''Despite the stampede to reform markets that essentially functioned well, none of the reformers' proposals would prevent another Black Monday from happening.'' Dan Seligman is an urbane, soft-voiced, unfailingly courteous colleague who transforms himself in these pages fortnightly into the curmudgeonly Dr. Keeping Up, an acerbic slayer of (mostly liberal) prig-headedness. In both personae, Super-Dan uses elegance and trenchant wit to wage his never-ending battle against fustian thinking, be it from overbearing bureaucrats, loony activists, or insufficiently rigorous colleagues. Now, after 37 distinguished years with FORTUNE, Dan has decided to retire as our associate managing editor. But you'll be happy to hear that he has agreed to continue, as contributing editor, to write Keeping Up. Since he started his inimitable column in 1976, he has produced it for 275 consecutive regular issues. With our readers, we rejoice that Dr. Keeping Up will continue to educate, lambaste, and entertain.