Hunting through audiobook catalogs for Lisa Kleypas has turned into one of my small, guilty pleasures — I love tracing how a beloved series gets translated into audio. In my experience the short version is: publishers generally try to release audiobooks in the same sequence as the printed books for a given series, but it isn’t guaranteed, and there are lots of practical reasons why the audio order can look messy.
Most mainstream series — think the 'Wallflowers' or the 'Hathaways' — do eventually get audio editions that match the original book order because publishers know listeners prefer continuity. However, rights sales, different audio publishers picking up backlists, and narrator scheduling can create gaps or odd release patterns. Sometimes a popular title like 'Devil in Winter' or a bestselling contemporary will get an audiobook early while earlier backlist entries only show up later as contracts are renegotiated or when a new distributor decides to produce the entire catalogue.
If you want to listen in order, I check the print publication dates and cross-reference them against the audio release dates on Audible, the publisher’s audio page, and my library app (OverDrive/Libby). I also watch for re-recordings — occasionally a whole series gets re-narrated and re-released, which is glorious if you want a single narrator voice through the series. Bottom line: the audio landscape follows the book order more often than not, but expect exceptions and keep a little checklist; it makes the hunt half the fun, at least for me.