Those coolly authoritative, gold-lettered sets of reference books that were once sold door to door by a fleet of traveling salesmen and displayed as proud fixtures in American homes will be discontinued, the company is expected to announce on Wednesday.

In a nod to the realities of the digital age — and, in particular, the competition from the hugely popular Wikipedia — Encyclopaedia Britannica will focus primarily on its online encyclopedias and educational curriculum for schools, company executives said.

The last edition of the encyclopedia will be the 2010 edition, a 32-volume set that weighs in at 129 pounds and includes new entries on global warming and the Human Genome Project.