The book deals with thinkers and movements that were embraced by many second-century religious seekers but which are now largely forgotten or known only as "heretics" Basilides, Sethianism, Valentinus' school, Marcion, Tatian, Bardaisan, Montanists, Cerinthus, Ebionites, Nazarenes, Jewish-Christianity of the Pseudo-Clementines, and Elchasites.

Antti Marjanen, Th.D. (University of Helsinki 1996), Docent of New Testament Studies, is presently working as a Research Fellow of the Academy of Finland. He is the author of The Woman Jesus Loved (Brill, 1996) and a translator and co-editor of a collection of Finnish translations of the Coptic Nag Hammadi Library (2001). His current research projects deal with influential women in Early Christianity and social-historical issues among second- and third-century Christians, traditionally called gnostics.
Petri Luomanen, Th.D. (University of Helsinki 1996), Docent of New Testament Studies, is presently working as a Research Fellow of the Helsinki Collegium for Advanced Studies. He is the author of Entering the Kingdom of Heaven: A Study on the Structure of Matthew's View of Salvation (Mohr Siebeck, 1998). His current research focuses on the textual sources of early Jewish Christianity, Jewish-Christian gospels and the socio-cognitive basis of hatred towards early Jewish Christians.