The numbering of this series was a continuation from Thor vol. 3. That series changed its name back into Journey into Mystery starting with issue 622, tying into Fear Itself. The series featured Loki as the main character from that point on and did so untill issue 645, after which his story was continued in Young Avengers Vol.2. Thor got a new ongoing series for himself when this series was started, namely The Mighty Thor (vol.2). From issue 646 the main character switched to Sif. The series lasted until issue 655, making it one of the longest collective series.