How can I look up and combine data from 2 spreadsheets?

I have two sets of data on two different spreadsheets. My goal is to grab data from Spreadsheet 1, and use it to consolidate more data on spreadsheet 2. For example, Spreadsheet 1 has data on columns A, B and C that I am interested in. Spreadsheet 2 has the same data as column A from spreadsheet 1, but is missing data similar to columns B, and C. My goal is to be able to use data on column A from Spreadsheet 2, look up some values in Spreadsheet 1 from and pull the data from columns B, and C and add such data into Spreadsheet as a new column D. Please help? Thanks.