[R] read.xls question

[Mathew, Abraham T]

I'm an R newbie and had a question about the read.xls function. I've heard that this is often not a reliable function to use for importing data. However, I have created numerous xls files which contain information about voter turnout and macroeconomic indicators in India. I'm writing a paper on the relationship between economic growth and voter turnout.
 
This is the command I use:
 
data <- read.xls("India.xls", header=TRUE)
 
I get the following error message:
Error: could not find function "read.xls"
 
 
Anyone have ideas?
Thanks,
Abraham