Stig Åvall Severinsen Ph.D. (born 1973, Aalborg, Denmark) is a four-time World Champion freediver and holder of two Guinness World Records. His lifetime passion for water and breath holding lead him to write the book “breatheology – the art of conscious breathing” which appeared in Denmark in 2009 with the title “Træk Vejret – mere energi, mindre stress”. It quickly became a bestseller and was subsequently translated and published in English in 2010 by Idelson-Gnocchi.