Dalrymple notes that in the last year more than 100 papers have been retracted due to falsified peer review:

Because of super-specialization, the authors of papers themselves are nowadays often asked to suggest referees for peer review of their own work, but this, of course, leaves an opening for the practice of fraud. In a modern variant on Gogol’s Dead Souls, some scientists have been caught sending their papers for peer review to non-existent reviewers, complete with a curriculum vitae and an e-mail address…There are even companies in China, apparently, that will help scientists to manufacture bogus peer reviews. A new twist would be for the rivals of those scientists to pay for bad reviews. Everything is possible in this crooked world of ours.