His latest series, published under the pseudonym "Adam Palmer", introduces the character of Daniel Klein, an expert on ancient Semitic languages.

[3] Kessler began writing at the age of 15 when he dropped out of school, but it wasn't until he was in his late thirties that he secured a publishing contract from Hodder Headline.

His first book A Fool for a Client was a legal thriller and courtroom drama about the trial of a 23-year-old female medical student in New York for the murder of an Irish nationalist who had fled to the United States and avoided extradition.

The book was reviewed by Susanna Yager in the Sunday Telegraph, who wrote: "The author has thought up the most ingenious method of committing murder that I have come across in a long time".

The entire book takes place in a 15-hour time-frame and was described by James O'Brien (radio presenter) on LBC as "a cracking thriller".

[10][11][12][13] 2011 marked a change of direction for Kessler with a new book, The Moses Legacy, a combination of conspiracy, historical and chase thriller about an expert on Semitic languages (Daniel Klein) who is called in to translate a sample of Proto-Sinaitic script found on the shattered remnants of ancient stones found in the Sinai desert by a female archaeologist.

Kessler – who lists Dan Brown as one of his influences (see below) – adopted the pen-name Adam Palmer to signify the change of style and genre.

[16] However, he also admitted that the inspiration for Mercy came from a conversation with a psychiatric nurse with whom he got talking when he called the wrong number while trying to contact an old friend.