CEO John Chambers said last week that Cisco Systems is "very close to the levels reached at the height of our industry's late 1990s activity prior to the downturn." The enthusiasm sprung from a 9% year-over-year sales gain to $4.8 billion for its first quarter ended Oct. 26. Cisco had net income of $618 million, compared with a loss of $268 a year earlier. However, Chambers remains cautious about the future, noting that the quarter's book-to-bill ratio fell below 1.0, a sign of slower sales. "CEOs are increasingly cautious about [capital-expenditure] spending and hiring until they see their own revenues and profits improve," he says. "Their visibility, in terms of their own revenues and profits, is in a number of cases becoming more limited."