Poisons Unknown is a vintage hardboiled mystery and crime fiction novel written by Frank Kane and originally published in 1953. The book is part of the author's popular, long-running detective series featuring the cynical, tough-talking New York private investigator Johnny Liddell. 

The story kicks off when Johnny Liddell is hired by a powerful New York gangster who offers him a hefty fee to track down a missing person named Brother Alfred. Brother Alfred is the elusive proprietor and leader of a bizarre, vice-ridden cult known as the "Eye Almighty Tabernacle," located just outside of New Orleans.