update table with missing data

[honor401]

I have two tables
table1 his a master list of companies that I have already delt with
table2 is a list of companies that I have delt with as well as new companies and I allow for multiple instances of company data to be in table2

table2 my have several records refering to "ABCD Inc" but table1 will only have it once

If new companies show up in table2 how can I get a mass copy of all the companies that are in table2 but not in table1 into table1?

thanks,
honor