These are some books written by members of the meetup.

Teaching Statistics: A Bag of Tricks

Andrew Gelman & Deborah Nolan

Learning R

Richard Cotton

Doing Data Science

Cathy O'Neil and Rachel Schutt

Parallel R

Q. Ethan McCallum

A Quantitative Tour of the Social Sciences

Andrew Gelman & Jeronimo Cortina

Machine Learning for Hackers

Drew Conway & John Myles White

Applied Predictive Modeling

Max Kuhn & Kjell Johnson

Machine Learning for Email

Drew Conway & John Myles White

Testing R Code

Richard Cotton

Analyzing the Analyzers

Harlan Harris, Sean Patrick Murphy & Marck Vaisman

R for Everyone

Jared P. Lander

Testing R Code

Richard Cotton

Bayesian Data Analysis

Andrew Gelman, John B. Carlin, Hal S. Stern, David B. Dunson, Aki Vehtari & Donald B. Rubin

Text Mining with R

Julia Silge & David Robinson

Bad Data

Q. Ethan McCallum