Encyclopedias have existed for around 2,000 years and have evolved considerably during that time as regards to language (written in a major international or a vernacular language), size (few or many volumes), intent (presentation of a global or a limited range of knowledge), cultural perspective (authoritative, ideological, didactic, utilitarian), authorship (qualifications, style), readership (education level, background, interests, capabilities), and the technologies available for their production and distribution (hand-written manuscripts, small or large print runs, Internet). As a valued source of reliable information compiled by experts, printed versions found a prominent place in libraries, schools and other educational institutions.