BOSTON -- At Fidelity Investments there's one big question right now: When is this state of perpetual revolution going to end?Because lately the conservative, family-controlled Boston firm has seemed a little more like the old Chinese Communist Party during the Cultural Revolution, with Chairman Ned Johnson, 77, playing the mercurial, mysterious and all-powerful role of Chairman Mao. Almost every other month, big shots mysteriously disappear, while others suddenly return from Outer Mongolia and are restored to favor. The latest is Rodger Lawson. He's one of old guard who worked with Johnson back in the 80s. He was suddenly called back to the fold in July and given the role of president. Lawson quickly unleashed a sweeping reorganization of the immense and byzantine firm, which employs more than 40,000 people and manages more than $1.3 trillion in assets. Yet the firm hasn't even settled down from the big revolution launched two years ago by Lawson's predecessor, Bob Reynolds. That time around, Reynolds and fellow firm veteran Stephen Jonas sought to turn around the struggling mutual-fund operation with broad changes in everything from the way fund managers were hired and promoted to the way Fidelity conducted its research. Where are Reynolds and Jonas now? Gone. Jonas quit suddenly in January. Reynolds, who had been Chairman Ned's right hand man for years, left abruptly in April. That was less than a year after he had, bizarrely, angled publicly for the job of NFL commissioner. The two men had been seen as possible successors to Chairman Ned in the inconceivable event that the old man, now 77, should ever die. Long-time Fidelity watchers said their departure was great news for another rising star, 53-year old Ellyn McColgan, the head of Fidelity's brokerage business.