"Our marriage was, from any conventional point of view, wildly implausible; and you, my dear son, are the miraculous product of this beautiful, rather crazy, and all too brief love affair."

When Dylan Riley received the devastating news that his wife, Emanuela, had cancer, he began writing blog posts describing the anguish and disarray brought by her worsening symptoms. Perdita is written for their teenage son, Eamon.

It is a lyrical memoir of a marriage, from their heady first encounters in Rome. It is also a raw and moving account of a bereavement. Cancer, Riley reflects, is a pitiless opponent. It drains hope of its power and turns it into self-delusion. Living with cancer is to experience a progressive foreshortening of time.

Next year might be terrible, but there can be a few good months now; tomorrow will likely be bad, but let's focus on today. Riley finds that hope itself, that tricky and dangerous emotion, grows out of the soil of our mortality, and of the mortality of those we love.

Perdita offers no advice. It tries more simply to represent a lost connection. "I wanted the world to know what it had it had lost," he explains, "and maybe in knowing it to make her live again."