The FTSE 100 hit an all-time high at the start of May, so does that mean it's a good time to invest? And if so, what are the best ways of investing into the stock exchange of the 100 most valuable companies in the UK? Which? Writer and researcher Megan Thomas & Hargreaves Lansdown’s Head of Money and Markets Susannah Streeter explain why now might be the best time to invest, plus what your options are if you’re just starting your investment journey. Find out what the best stocks and shares Isas are & which investment platform is best. Read our tips for new investors & sign up to our free weekly Money newsletter.