Contribution is generally by invitation, and contributors are recognized as leading international specialists within their field.

[1][2] The IEP was founded by philosopher James Fieser in 1995, operating through a non-profit organization with the aim of providing accessible and scholarly information on philosophy.

[4][2] The entire website was redesigned in 2009, moving from static HTML pages[citation needed] to the open-source content management system WordPress.

The intended audience for the IEP is philosophy students and faculty who are not specialists within the field, and thus articles are written in an accessible style.

[2] During any twelve month period it receives 6.9 million unique viewers, making it the most visited encyclopedia of professionally written philosophy articles.