if (! require('SnowballC'))
    install.packages('SnowballC')
library(SnowballC)

readBookFromFile<-function(path, range=NULL, stem=FALSE) {
    lines<-readLines(path)
    if (is.vector(range))
        lines<-lines[range]
    lines<-tolower(lines)
    lines<-lines[lines!=""]
    words<-strsplit(lines, '\\W+')   
    words<-unlist(words)
    words<-words[words!=""]
    if (stem)
        words <- unlist(wordStem(words, language="english")   
    return(words)
}

# example usage:
#    md<-readBookFromFile('<path-to-file>/moby-dick.txt', stem=TRUE)
#    md<-readBookFromFile('<path-to-file>/moby-dick.txt', range=1:100)
#    ts<-readBookFromFile('<path-to-file>/tom-sawyer.txt', range=1000:2000,stem=TRUE)