Alongside the letters I'm walking with today, my studio guest is Howard Barlow, a photojournalist who, for 50 years, has worked regularly for The Guardian, The Observer, The Telegraph, The Sunday Times and The Independent. He's picked up numerous photographic awards, including Newspaper Photographer Of The Year.

Also, today, a wondrous hatful of first-time writers, we talk about design that makes life easier, photography that makes life happier, and we learn how photography was an ever-present friend in the face of physical adversity. There are several whys of photography to answer, and atop that, Marissa Roth, a Pulitzer prize-winning photojournalist, answers a question of ethics. There's also the final chance to take part in this month's one-word assignment.

Links to all guests and features will be on the showpage, my sincere thanks to MPB who sponsor this show and the Extra Milers without whom we wouldn't be walking each week.

WHY: A Sketchbook of Life is available here.