We like to think that science is completely objective and scientists are absolutely certain of their theories. But ask any scientist how they reach their conclusions and you’ll be surprised to see them talk about doubt rather than certainty, about what might or could be rather than what is true.

Ed Caesar, journalist and author of Two Hours: The Quest to Run the Impossible Marathon gives his top tips for getting faster, whatever kind of runner you are.

Read an extract from Mindware, Richard Nisbett’s practical guide to the most powerful tools of reasoning ever developed.

Jordan Ellenberg, author of How Not to Be Wrong on why mathematics isn’t just about linear curves and quadratic equations and why practice makes perfect when it comes to mastering the art of numbers.

John Lewis-Stempel, farmer and author of the 2015 Wainwright Prize winning Meadowland, witnesses the delivery of a brand new sheep in this beautiful exclusive piece.

Naomi Klein’s This Changes Everything has just kicked off the Guardian’s major project on the climate crisis. Read an exclusive extract from the book’s conclusion.

Dale Shaw muses on whether we really are in the future (it is 2015 you know), according to predictions from classic science fiction authors.