In this talk, Tal Galili, the founder of R-bloggers, will present his recent work "dendextend," a package intended for visualizing and comparing trees of hierarchical clusterings (a.k.a: dendrograms) with R. This talk was recorded at the New York Statistical Programming meetup at Knewton. Tal begins his presentation with a short overview of "dendrogram" object in R and its manipulation with the "dendextend" package. He then discusses how to create, change, visualize, and statistically compare two trees of hierarchical clusterings (with some sprinkles of Rcpp). Tal ends with a 5-minute lightening talk teaching how one can quickly update R on windows/mac, using the 'installr' package.