Letters From Leonard by S.E. Kennedy
When Paul receives a phone call telling him his best friend has committed suicide, he begins reading Leonard's old letters in an effort to find out why. This turns into a journey of discovery as Paul becomes obsessed with tracing his friend's steps over the last days and months of his life. Along the way, he comes face to face with his own demons and self-destructive nature as he risks everything including his job, his marriage and his family, to put the ghost of his friend to rest.