THE MERCHANT'S WAR by Fredrick Phol (St. Martin's: $13.95). Phol pits "Veenies" (human emigrants to Venus who prefer food in its natural state and honest candor such as "All cocktails are canned premixes, and they taste like it.") against Earth-dominating ad agencies (inventors of unfulfilled promises and champions of civilization and Reel-Meet). Phol uses satire to laugh at and reflect on advertising and our culture of eager consumers. This is a witty sequel to Phol's 1953 book, "The Space Merchants." Gaudeat emptor .