$article_date = $custom["tf_book_author"][0];
$article_date = $custom["tf_book_afirst"][0];
$article_date = $custom["tf_book_isbn"][0];
$article_date = $custom["tf_book_dts"][0];
$article_date = $custom["tf_book_price"][0];
This is your issue. You need to set these to $tf_book_author
and such, especially if you’re going to echo them. I stopped there, so there may be more errors in the code, but that’s the first one to knock out.