use the following code,

print "$data->{Book}->[0]->{author} is the author of $data->{Book}->[0]->{title} and it is published by $data->{Book}->[0]->{publisher}\n"
print "$data->{Book}->[1]->{author} is the author of $data->{Book}->[1]->{title} and it is published by $data->{Book}->[1]->{publisher}\n"

instead of print "$data->{author} is the author of $data->{title} and it is published by $data->{publisher}\n"

Note: Suppose, input has 100 <Book> you are using the loop accordingly.

Thanks
Sakthi