What is the fine-grained topic of the following text: From 1965, while working by day in a men's outfitters shop and playing by night with his semi-professional band, he wrote a string of million-selling hit songs: as well as "For Your Love" he penned "Heart Full of Soul" and "Evil Hearted You" for The Yardbirds, "Bus Stop" and "Look Through Any Window" for The Hollies, "No Milk Today" and "Listen People" for Herman's Hermits, "Pamela, Pamela" for Wayne Fontana, "Behind the Door" for The St. Louis Union and Cher, "Tallyman" for Jeff Beck. Only return the topic.
The songwriting career of a semi-professional musician in the mid-1960s.