The book appears to be unironic non-fiction, judging by the Table of Contents.
This is the only book credited to Curtis Lavender. From Chapter One:
I will call myself Curtis Lavender in these pages. Curtis Lavender because that was my name in another life. I cannot tell you my real name or where I work because that would jeopardize my life and my religion. I am pledged in blood to secrecy and the curse of Satan will be upon my head if I reveal too much.
Witchcraft and Satanism are wholly different practices, but the two are frequently muddled, especially after the phenomenal success of Rosemary’s Baby, both Levin’s novel (1967) and Polanski’s faithful film adaptation (1968).
Cover art to the Lancer edition of Confessions of Warlock is by Ron Walotsky.