From "Review in progress" to "Ready to review" I understand that this question is related to a workflow of a journal and have tried to look at the answer of this specific query but am not able to find a specific answer anywhere else. The query is 
I had send a paper to a reputed journal. Its status for the past month was "Review in progress". After more than a month, its status changed to "Ready to review". What does this mean? How could the status for atleast one month be "Review in progress" and then change to "Ready to review".
I had a similar experience. I contacted the Editor, and it turned out that one of the reviewers they contacted backed out of reviewing my paper, so the progress went back to something like "ready to review" (not those exact same words, I can't remember the exact status, but basically is a step back from being reviewed or in progress). I never would have known that if I didn't contact the Editor. A polite email to the editor won't hurt. IMHO.