I have just finished it and I think it is a good book. It is worth
reading his "Once a Runner" first since "Again to Carthage" is a
sequel to it. Moreover, Parker does not spend time introducing the
characters and somewhat assumes that the reader is familiar with the
first novel. OaR achieved a cult status among people who enjoy the
sport. OaR is out print but copies are scanned in and available on the
Internet.

"Again to Carthage" is a more complicated book than OaR. The
characters are given a bit more depth. It is also not just about
running. One of the major characters (from the first book) goes and
dies in Viet Nam. The wistful and somewhat despondent tone is more
pronounced in the sequel as the protagonist -- Quenton Cassidy (and
the author) had to come to terms with the sunset of their running
career. Quenton Cassidy is well aware that the race, set in the end of
the book, is his swan song. Yet, this very race and the reckless drive
for physical perfection come out as the victory against inevitable
decline and the affirmation of the joy of life itself. The description
of the race and the book's ending, reminiscent of the first book's,
are quite moving.

Parker is a former elite runner. He essentially writes about himself
which brings to the novels the raw authenticity that won the first
book so many admirers among runners. Actually, the novel is structured
as a sequence of notes written as if by a runner in heavy training as
an escape from the grind of the routine and torment of twice-daily
workouts. The book has its weaknesses. A letter from Quenton to his
girlfried that takes up a whole chapter is rambly at best. The
arch-villain is painted with a broad black brush. He is introduced
nearly at the very end of the book just late enough for Quenton to
raise the stakes. Overall, the narrative's direction weaves, turns and
occasionally seems to be lost. However, the books sincerity and
authenticity is certain to endear the book to generations of runners.