Expanded Genasi is a short but packed pdf detailing 12 new genasi sub-races. Jonathan Sutton gives a quick re-printing of the base genasi racial traits (handy to keep the number of books/pdfs open at your table to a minimum) before diving right in to cover genasi of the para- and quasi-elemental planes. Each genasi presented has thematically-connected and reasonably unique racial traits, happily departing from the standardized Race Analysis Guide's stock list of traits. Many of the traits presented promote thoughtful use of powers in specific situations rather than permanent ambient bonuses.
This work is clearly meant for players and DMs who have a decent understanding of D&D's historical inner plane cosmology. Those who are just getting into gaming may not understand where these genasi fit in (a "planar explorer's travel sketch" might help such new players immensely or a sidebar explaining what sub-planes arise from which planar boundaries overlapping). Those wishing to depart from the Great Wheel cosmology will have to decide for themselves how these genasi are born and how the main genasi view their cousins.
For those who are incredibly uptight about such matters, the Table of Contents is incorrect and there are a few grammatical errors. However clicking on the Table of Contents still brings the reader to the correct page they were looking for and the errors are rare and subtle.
Overall, a wonderful expansion of the genasi races for 5th edition and an excellent first publication!
[4 of 5 Stars!]