THE HYPNOTIST is a fast-paced medical thriller that, even though weighing in at 500 pages, is so full of action that it does not take long to whisk through. Set in Christmastime Stockholm, the reader is plunged right into a description of a family that has been brutally murdered. The only survivor is the teenage son, Josef, who is horrifically injured and so hospitalised. Joona Linna, the (Finnish) detective in charge of the case, soon realises that one other family member is still alive, but is likely to be in grave danger from the unknown assailant. Hence, he calls in Erik, the titular hypnotist, to see if he can be persuaded to dig into the unconscious victim's mind for clues as to the crime. Erik, however, has vowed never to practice hypnosis again (we don't yet know why) so he has an ethical dilemma about whether to agree and, if he does, in whose interests he is acting.

Before Joona and Erik know it, the tables have been turned on them and the investigation takes an abrupt shift. This constant change in direction continues, as our perception of who is criminal and who is victim never seems to stay the same for more than a few pages, leading up to one section in the middle of the book in which Erik reflects on his 10-year-old psychotherapy group and a failed experiment in shared hypnosis: could his actions then, be relevant to a horrible dilemma in which he now finds himself? I certainly questioned the wisdom and medical ethics of putting six highly unstable people in a room (including a violent male war criminal and several rather mad women), hypnotising them all together, and letting them witness each other's revelations, but the reader can see whether or not Erik's methods were justified in retrospect. Either way, this section of the book supplies several more possible suspects and red herrings, leading to yet more dangerous situations that have to be experienced before the inevitable apocalyptic denouement.

If you enjoy a thriller, particularly one in which you never know who is going to leap out of a dark corridor wielding an axe, then this is a book for you, provided you don't mind lots of blood and gore, and are willing to stretch several points of belief - such as the ease with which someone in a virtual coma, with multiple stab wounds and a collapsed lung, can go skipping across a graveyard, attack a motorist and steal his car. Those who enjoy more reflective, rounded books had better look elsewhere.

The authors (a husband and wife writing pseudonymously) are at their strongest when describing Joona's investigation and the dynamics between Erik, his wife Simone and their son Benjamin. Although the book as a whole is exciting, I felt that by its end the authors had somewhat lost touch with the initial crime and why it ever happened, preferring sensationalism to depth.