These are some books written by members of the meetup.
Q. Ethan McCallum
JJ Allaire
Hadley Wichkam
Max Kuhn & Kjell Johnson
Richard Cotton
Jeroen Janssens
Cathy O'Neil & Rachel Schutt
Jared P. Lander
John Myles White
Wes McKinney
Mike Dewar
Hadley Wickham
Bryan Lewis and Michael Kane
Andrew Gelman, John B. Carlin, Hal S. Stern, David B. Dunson, Aki Vehtari & Donald B. Rubin
Max Kuhn
Rob Hyndman
David Robinson
Harlan Harris, Sean Patrick Murphy & Marck Vaisman
Andrew Gelman & Deborah Nolan
Julia Silge & David Robinson
Andrew Gelman & Jennifer Hill
Tony Fischetti
JD Long
Andrew Gelman
Drew Conway & John Myles White
Paul Dix
Daniel Y. Chen
Andrew Gelman & Jeronimo Cortina
Chris Fregly & Antje Barth