Searching Titles Based on Keywords

Here is a design question: I have a database of book titles each associated with several keywords. How should I organize to have the best performance: - keywords associated with each title share one field separated by comma; - each keyword occupies one field - the BOOK table contains five keyword fields: KEYWORD1, KEYWORD2, ... Could someone tell me if the first approach is efficient enough (assuming it's indexed normally)? Thanks in anticipation. Yudong