Virginia Savage McAlester - Leading the Ultimate House Tour - NYTimes.com Dallas - If Virginia Savage McAlester were going to die of leukemia, the right time would have been before she ordered a new Texas historical marker for her house. Space on the plaque was at a premium: The 6,000-square-foot home has been in the family since 1921, and her patrician forebears have played an influential role in the city for most of those years. "For a long time, it was thought of as the Savage house," she said on a recent Saturday morning. Wallace Savage, her father, served as the mayor of Dallas from 1949 to 1951. Her mother, Dorothy Savage, rescued dilapidated houses up and down the street, Swiss Avenue, helping to spur the city's preservation movement. "And before that," she added, it was "the Harris house." Her grandfather William R. Harris was the trial lawyer and political operator who led the impeachment of Gov. James Edward Ferguson in 1917. Ms. McAlester's own epigraph - or would that be an epitaph? - would label her as an author and "the Queen of Dallas Historic Preservation," a term suggested by a fellow architectural historian, Stephen Fox of Houston. Ms. McAlester mused, "The advantage of my dying during the stem-cell transplant is I could have had my name on the historic marker, too." Joining history, alas, would have gotten in the way of writing history. At the same time that Ms. McAlester, 70, was receiving treatment for myelofibrosis, she was engaged in the decade-long labor of updating her magisterial book, "A Field Guide to American Houses: The Definitive Guide to Identifying and Understanding America's Domestic Architecture." The first edition, published in 1984, told the illustrated story of why our houses - great and humble and everything in between - look the way they do. For six years back then, she had collected copies of some 100,000 house photos, many from the Library of Congress, and pinned them on a giant corkboard. Picture the tormented detective in a thriller, rearranging mug shots, with bits of red string. Yet the mystery for Ms. McAlester was cloudier. What would a Queen Anne-style house look like without a tower? Why did some Craftsman houses have the half-timbering of a Tudor on top? Ms. McAlester methodically compiled a pictorial glossary of cross gables and wall dormers, pediments and entablatures. Of the latter pair, she said: "Those are two words I didn't know when I started to write this book. I had to learn a whole architectural vocabulary. She had drafted the early chapters with her second husband, Lee McAlester, then the dean of humanities and sciences at Southern Methodist University. In academia, he had published two textbooks summarizing the geological saga of the planet. "He had this theory that if he could do the history of life and the Earth, surely I could deal with houses," Ms. McAlester said. Their marriage evolved into a divorce on an almost geological timeline, after she moved back to the family home to care for her ailing parents. But for all her completism, the first edition of "A Field Guide" essentially ended in 1940. Some 80 percent of American homes, she explains now, have been built since then. The original chapter on tepees had stood the test of time. But what about newer dwellings, like manufactured housing and millennium mansions? In Ms. McAlester's democratic scheme, they are not "mobile homes" and "McMansions." And how could a history of American houses be comprehensive while ignoring platting and streetscapes, the operating system of neighborhood development? The revisions had proved hard enough when she still possessed a steady supply of red blood cells carrying oxygen to her brain. Yet if Ms. McAlester wanted the work to outlive her, she would have to finish it. And so she did: The book came out this month from Knopf ("almost on schedule," Ms. McAlester writes). While she was at it, she seems to have managed a complete recovery from her illness. The acknowledgments in the second edition include photographs of the cure cottages at City of Hope, a hospital complex in Duarte, Calif., where she recuperated through the summer and fall. She categorizes them as midcentury modern, taking special note of a shed-style roof.