The second edition of my book, Phononic Crystals - Artififial Crystals for Sonic, Acoustic, and Elastic waves, has been published by Degruyter. It can be obtained from Degruyter's website or from book resellers such Amazon. There is new material on perfectly matched layers (PML) for instance, and a full new chapter on topological phononics and symmetry. Please feel free to review or comment the book onlne, e.g on Amazon.