Audrey The most recent book is a presequel. I have read that and the first two books. I think it helps to read them in order since their are characters who evolve from one book to the other. I really like them. I dont just read them one after the other. Read one and then go on to the next in a month or so. Another great series is the Mathew Shardlake mysterys that take place during the reign of Henry VIII.
Sandy I've now read two of about 7. I happened to read them in order although this was completely by accident. They are certainly enjoyable reads as stand alone books but when characters carry from book to book and there is a thread of an underlying story, I like to read them in order to stay with the thread. By the way, I've just requested the third in the series from the library, rather than jump ahead and read a later one. In any case, enjoy your reading!