Addressing the widespread use of mood altering substances in our culture, this thoughtful study examines their moral implications through the lens of Catholic philosophy, theology, and sound science. It explores the relationship between pleasure, pain, and authentic human flourishing, clarifying the differences between therapeutic and recreational use and between true joy and fleeting delight. With careful distinctions and practical guidance, this book equips readers to form their consciences wisely, order their emotional lives rightly, and pursue lasting happiness rooted in truth and virtue.