"Hints on Child-training" by Henry Clay Trumbull can be considered one of the first popular parenting handbooks. Published in the late 19th century, the book aims to teach parents and soon-to-be parents how to properly raise their children to later be functioning and productive members of society. Though many of the pieces of parenting advice in the book are now woefully outdated, being able to read and compare past norms to current ones is still well worth a read.
