\u201cCloud is in every conversation I have these days,\u201d the CIO of a major Wall Street firm told me recently, sounding surprised. \u201cLast year I was making fun of it. Now we\u2019ve become a cloud provider. I\u2019m still a little amazed.\u201d\n \n In just a year, this CIO\u2019s private cloud had turned into a revenue-generating service attracting growing numbers of customers. Like many of the demanding, tire-kicking executives we talked to for this special issue on the wisdom of clouds, this Wall Streeter has become a cloud believer.\n \n Against all odds\u2014in an IT industry that swoons over one overhyped technology trend after another\u2014something real is going on here. There is wisdom in taking a serious look at what cloud has to offer your business.\n \n What you\u2019ll find in these pages is basically wall-to-wall reality, or, as our Special Issue Editor David Rosenbaum calls it, \u201cAll cloud, no fluff.\u201d\n \n \u201cHow Cloud Computing Rose From Lehman Brothers' Ashes,\u201d by former Wall Street Journal reporter Bill Bulkeley, gives us the inside story of how the bankrupted Lehman Brothers is being oh-so-carefully dismantled in the cloud. It\u2019s also an illuminating tale of business agility and creative risk-taking by the IT leader in charge of this almost surreal assignment.\n \n For a punch of cold hard calculation, try \u201cWhat the Cloud Really Costs: Do You Know?,\u201d which points out how tough it can be for an IT organization to dispassionately stack up cloud computing against its internal operations. The story delves into capacity planning, integration costs and other real-world practicalities that affect the bottom line of cloud decision making.\n \n Of course, for some companies, the cloud decision is almost a no-brainer. In \u201cHow Cloud Computing Promotes Business Growth,\u201d you\u2019ll find four case studies of fast-growing companies using cloud to scale quickly to seize market opportunities. As one IT executive explains it, \u201cWe\u2019ve pushed ourselves to place a big bet on how we think the future will unfold.\u201d\n \n And as it unfolds, CIOs need to \u201cget smart and get specialized,\u201d contends Stanford University Professor Timothy Chou, who tells you how to do just that in \u201cWhy Cloud Computing Is Not Just a New Name for Outsourcing.\u201d Chou, who once ran Oracle\u2019s On Demand business, points out that the lessons of all those IT mega-transitions of the past (from mainframes to client\/server to Web) can guide CIOs\u2019 thinking now.\n \n For CIOs, it\u2019s a time to be thoughtful, and very, very careful. \n \n As any pilot can tell you, real dangers sometime lurk in those pretty, fluffy clouds.\n Maryfran Johnson is the editor in chief of CIO Magazine & Events. E-mail her at email@example.com.