It’s difficult to explain how a chance encounter led to a lifetime gig, and why a spinoff of the original idea took 36 years to come about — let alone why such a book is relevant in the age of the Internet. But I’ll try.I was 17 when an editor at Signet Books put his faith in me and gave me the assignment of compiling a paperback reference guide to movies shown on television. (This was long before homevideo, premium cable or satellite channels, in the Cro-Magnon era of television when local stations programmed old movies throughout the day and into the wee hours of the morning.) Originally published as “TV Movies,” the book is now known as “Leonard Maltin’s Movie Guide.” This past month it spawned a companion volume, “Leonard Maltin’s Classic Movie Guide” (Penguin/Plume). The first edition of “TV Movies” listed 8,000 films. I hired several people to help me put it together, and during the long road to publication, I learned my first lesson about reference books: It’s all about editing and fact-checking. Every draft got better, every pair of eyes noticed something the last ones hadn’t. When I held the finished book in my hands, all I could see were its shortcomings, but it was surprisingly well received. I thought of it as a fingertip guide to movies, not a serious reference work, and I pictured our average reader being the kind of film buff who stayed up late watching movies on TV. Imagine my surprise when I started hearing from newspaper and magazine editors, film programmers at TV stations, salesmen for major-studio TV libraries and others in the business who told me that it was their primary source of information. One day I called a studio, trying to find someone in the print department who could give me reliable running times. I got a nice fellow on the phone, and when I asked him where he acquired his numbers, he said, sheepishly, “We use your book.” This was highly flattering, even if it wasn’t the answer I was looking for. Over the years, I’ve been lucky to gather a terrific team of colleagues who write and edit the book with me. We work hard all year long, and sharp-eyed readers keep us on the ball, catching any mistake we may commit. The advantage of being an annual publication is the knowledge that when we make an error, we can fix it the following year. The biggest challenge during the past decade has been cramming everything into a finite amount of space. The first edition of the book listed 8,000 movies; that number eventually swelled to 19,000, at which point my publisher informed me that the book could get no thicker. Something had to go. We typically add 300 entries a year; that meant pruning at least as many titles to make room for them. In time I came to the difficult conclusion that made-for-TV movies would have to go. They deserve a reference guide of their own. Then it came to a point where I was forced to trim theatrical titles as well (obscure ones, I grant you, but every cut was like a knife in my heart). Well-meaning people suggested that I turn the book into a two-volume set, but its success has always depended on its reasonable pricetag and its ability to rest on a night table or TV set. Expanding to two volumes would defeat both of those points. My daughter Jessie had the idea of devising a separate book on old movies that wouldn’t replace the annual guide but serve as a supplement instead. This seemed to be the perfect compromise. The “2006 Movie Guide,” which we’re in the process of completing for publication in August, will still be a broad-ranging book where you can look up “The Gold Rush,” “The Wizard of Oz” or “Singin’ in the Rain,” as well as the newest releases of this year, but lesser-known films of the past have been shuttled over to the “Classic Guide.” This has given us a little breathing room and even enabled us to restore a feature we had to sacrifice five years ago, a Directors Index. As for “Leonard Maltin’s Classic Movie Guide,” it seemed to me that since we had room, we might as well make the most of it. In addition to restoring titles we’d cut from the annual edition, we’ve added 1,100 old movies we’d never covered before, the kind of films now being resurrected on DVD and shown on Turner Classic Movies, Fox Movie Channel, Encore Western and other outlets. We’ve even catalogued, for the first time, the complete works of Roy Rogers, Gene Autry and Hopalong Cassidy. The response has been encouraging. Even in the age of online data banks, people seem to like the idea of knowing who is supplying their reviews and information. Although it never occurred to me 36 years ago, we’ve become a “brand” people seem to trust.