Industry guru Mike Shatzkin foresees big gains in e-book sales, consolidation among literary agencies, a jump in customized book sales and much more…. You won’t catch me climbing out onto any billion-dollar limbs as I offer my forecast for book publishing in 2008, but some of the changes I envision do call for fundamental changes in how the business operates. There is an overarching theme to the changes already taking place. Consumer media in the 20th century tended to be horizontal and format-specific. The New York Times and Random House define “horizontal”: they publish across all interests and markets. The Internet will drive 21st-century publishing enterprises to be more like what professional publishing has always been: highly vertical and format-agnostic.