This is the final part of Richardson's collection entitiled Early Christian Fathers. - volume 1 of the Library of Christian Classics. This is a limited selection of some highlights from Books 1, 3 and 5 of Irenaeus's classic Against Heresies.
Irenaeus' work is one of the most significant witnesses of the faith of the Church c. 200, or at least the faith of the "winners" of what became Christianity. As the introduction points out, he is still viewed as interesting by today's theologians. These limited selections are actually quite limited, but do include many significant passages. I hope it is enough to make you interested in reading more.
SDG
Ken McGuire