Were 'An Accidental Light' a biographical work based on fact it would fall within the 'misery memoirs' genre; that peculiar group of books that seem to revel in telling utterly depressing tales of personal suffering, often in childhood (e.g. Angela's Ashes, A Boy Called It, etc.) By being a work of fiction it escapes this tag but that doesn't make it any more of an uplifting experience. Like other novels that ruminate on the impact that the death of a child can have on those around them, such as Sebold's The Lovely Bones, An Accidental Light is a rather maudlin literary experience. Experiencing bereavement and guilt, the two emotions displayed by the key characters, is not particularly enjoyable and I wonder why anyone would volutarily choose to so, even vicariously via a work of fiction. At some point we all experience loss in our lives, and possibly guilt too; why voluntarily seek both out in the books we choose to read?
I guess you could argue that novels dealing with the issues surrounding death, loss, guilt etc can offer some sort of profound insights into the human condition, providing a justification for reading them. An Accidental Light however, provides no such profound insights. Its handling of the issues it wants to address veers from the trite to the unrealistic. For example, if Elizabeth Diamond wanted to say something serious and truthful about the subjects her book deals with why include the paranormal as a plot device?
This is a shallow book of little merit that wishes to be taken seriously as a meditation on weighty emotional issues but in fact is nothing more than the fictional equivalent of those selacious 'true life tales' that are the stock in trade of many weekly magazines. It cheapens and sensationalises what in reality would be terrible events and the heartbreaking emotional responses to them. Avoid.