This is an amazingly dense, well-researched, and meticulously sourced treatise on the drow goddess Eilistraee and her followers. The breadth and depth of infomation included is incredible, and this resource is invaluable for campaigns or players seeking to incorporate Eilistraee into their campaigns. No stone seems to have been left unturned in the author's research, and an extensive works cited page allows the reader to delve even further into the stories of Eilistraee by tracking down the materials referenced. This is exceedingly handy for drow-centric campaigns, or anyone seeking to explore non-Lolthite drow.
I have a few small reservations about the systems presented for Sword Dancers, though I have not seen them in play, I feel that the alternate spellcasting ability and effective immunity to opportunity attacks create balancing issues (I would recommend a disengage bonus action every turn to correct the latter.) I also find the background texture a bit distracting, in particular, the center fold on each page. There are also a few sidebars that the shading seems misplaced on.
Overall, I recommend this product, despite my relatively minor critiques.
FOLLOW UP: I do look forward to the changes the author talks about below and will be happy to revisit upn updates. I too cannot WAIT to see what Tome of Foes has in store!