Mer Barr's review of The Usual Santas: A Soho Crime Holiday Anthology by Peter Lovesey and Helene Tursten and Mick Herron and Martin Limón and Timothy Hallinan and Teresa Dovalpage and Mette Ivie Harrison and Colin Cotterill and Ed Lin and Stuart Neville and Tod Goldberg and Henry Chang and James R. Benn and Lene Kaaberbol and Agnete Friis and Sujata Massey and Gary Corby and Stephanie Brown