I would recommend reading Intelligent Investor first. It was written slightly more recently (1949) than Security Analysis (1934). More important is that a recently revised edition* of Intelligent Investor was published. The preface and appendix were written by Warren Buffett. Intelligent Investor is more practical as an introduction for a novice. You may decide not to read Security Analysis at all, as it seems more like an academic text or professional's guide i.e. for accounting.
Benjamin Graham's Intelligent Investor remains relevant. It is used, successfully, as a guide for value investing, despite the hysteria of market sentiment and day-to-day variations, even extreme volatility. For example, I just read a nice article about applying the value investing principles extolled in Intelligent Investor a few weeks ago. It was written in the context of current markets, which is amazing, to be so applicable, despite the passage of decades.
For reference, you might want to glance at this book review (published in March 2010!) of the original 1934 edition of Security Analysis.
* The URL links to a one-paragraph summary by
U.S. News & World Report. It does not link to a book sales website!