For the past 50 years, we've been putting love under the microscope. Together we are probably the most famous love and marriage experts in the world, with more than 40 books between us and a hatful of academic posts and awards. 

John has even been called 'the Einstein of Love'. All our working lives, and today at our world-famous research centre, the Love Lab in Seattle on the west coast of America, we have focused on one question: what makes love last? 

Why does one couple stay together for ever, while another falls apart? And is it even possible to quantify any of this with data — to use the tools of science and mathematical modelling to predict whether a couple will live happily ever after? The short answer is: yes — to all of that. 

As psychologists and authors, we've studied more than 40,000 couples, some for as long as 20 years. We've watched countless hours of tape. Aggregated millions of data points. And what we've discovered is that there are universal factors that make or break a relationship, that predict whether a couple will stay together or not. 

There is a science of love. Like the Large Hadron Collider smashing apart an atom, we've isolated its building blocks. After all this time, love is no longer such a mystery. The great news is that it is possible to take what we've learned and use it to build a love that lasts for you. In our new book we've devised a bite-sized, seven-day action plan.