In a bulletin, the FBI says that the popular reference books covering everything from abbreviations to weather trends could be used by terrorists "to assist with target selection and pre-operational planning."
The FBI noted that use of almanacs or maps may be innocent. But it warned that when combined with suspicious behavior, such as apparent surveillance, a person with an almanac "may point to possible terrorist planning."
The senior editor of The World Almanac says he doesn't think anyone considers it a "harmful entity." He says most of data's on the Internet anyway.
And the publisher for The Old Farmers Almanac says terrorists would probably find statistical reference books more useful than in the publication's collections of Americana, weather predictions and witticisms. Still, he promised to cooperate with authorities.