What font should I use?

Someone asked the other day: "What font should I use to be sure that it will be easy to read?" There has been one piece of publicly available research carried out in the English-speaking world into what fonts and styling in text makes it easiest to understand the content. This was by Colin Wheildon in Sydney in the 1980s and was republished three years ago as Type & Layout: Are you communicating or just making pretty shapes. It was carried out by printing sample articles of the kind intended for magazine or newspaper use and measuring the comprehension by asking questions to show whether the participants understood the content. There's a downloadable extract of the book at http://worsleypress.com/type/ and the book is available from Amazon as well as elsewhere. A couple of comments: This is based on whether the font choice and styling actually work, not whether they look good, and it is a book not only unpopular but campaigned against by some graphic artists. It also applies only to English speaking countries -- the very limited tests in European countries infer that sans may do relatively better than serif in that region. It was also mainly conducted with narrow columns -- newspaper and magazine style rather than books. I'd also better declare my interest -- I played a role in returning the book to print though I no longer have any ownership in the business which does publish it. It is sad that this is the only work which is based on research rather than opinion. Some work has been done privately on behalf of major publishing groups and associations but is not publicly available.