Annual Review of Nuclear and Particle Science, 2017

It gives me great pleasure to once again write a review of what is an important collection of review articles published year after year in the fields of elementary particles and nuclear physics, and indeed more recently in the field of astroparticle physics as well. This year, the volume is significantly slimmer than in previous years with 11 articles which is significantly smaller than the typical 20 or so articles that appeared earlier. However, what is lacking in quantity is easily compensated for in quality as each of the articles is a precious little gem in the field.