Trichology Course aimed at practitioners who desire more knowledge about hair but do not want to become fully qualified trichologists. This is offered by home-study but also taught in America and Singapore. A Chinese version of this course is available. Registered members of the IAT can use the letters "IAT" after their name. Members are controlled by a code of ethics. Trichology Trichology is the branch of dermatology that deals with the scientific study of the health of hair and scalp. Trichologists are hair and scalp specialists (one type of skin specialist) who diagnose the causes of hair fall, hair breakage,
What Is and What Should Never Be descending riff [of "What Is and What Should Never Be"] is amazing: It's like a bow is being drawn back, and then it releases. The rhythm of the vocals is almost like a rap. It's insane — one of their most psychedelic songs." This was also one of the first songs recorded by the band for which Robert Plant received writing credit. According to rock journalist Stephen Davis, the author of the Led Zeppelin biography "Hammer of the Gods: The Led Zeppelin Saga", the lyrics for this song reflect a romance Plant had with his wife's younger sister. "What Is