Anna I'd recommend starting with 'Alpha and Omega' novella that acts as a prequel. The novella tells how the main heroes met and 'Cry Wolf' takes place just several days later and continues their story, so there is no repetition there. Besides, I think it will be more difficult to understand what's going on if one reads 'Cry Wolf' without reading the novella.
Alexandria I read Shifting Shadows, Briggs' short story collection, before I read Cry Wolf. The origin of Anna's story is in that collection and while it is possible to read Cry Wolf without it, you will lose a lot of understanding with Anna's character development and why she is the way she is in this series.