Essays in Radical Empiricism (ERE) by William James is a collection edited and published posthumously by his colleague and biographer Ralph Barton Perry in 1912. It was assembled from ten out of a collection of twelve reprinted journal articles published from 1904-1905 which James had deposited in August, 1906, at the Harvard University Library and the Harvard Department of Philosophy for supplemental use by his students. Perry replaced two essays from the original list with two others, one of which didn't exist at the earlier time.
Because ERE is a collection of essays written over a period of time, and ultimately not selected or collated by their author, it is not a systematic exposition of his thought even though Perry suggests otherwise in his preface. This circumstance, in addition to the evolution of James own philosophic stance, has contributed to a wide variance in understanding, misunderstanding, and critical opinion of radical empiricism.