Q.E.D. (1982-1999)

Ben Johnson believed in anabolic steroids; so did other banned athletes. But now there is evidence that these drugs' only real effect could be all in the mind. Backed up by the personal experiences of international athletes David Jenkins and AI Oerter, the results of scientific trials point to a startling possibility: despite positive drug tests, athletes may win titles entirely due to talent.

Alun's brother died of it at 34; so did his sister; Alun is past his 34th birthday and as he says, living on borrowed time. FA is Friedreich's Ataxia; sweet says Alun Jones , because of the diabetes he suffers along with it. Sweet FA is the title of his autobiography; but it could be his comment on government spending on research into this progressively crippling, inherited disease. Not that Alun or his family complain. They do all they can to raise money to support the research project trying to discover the faulty gene which causes this cruel disease and find a cure. But should this kind of research be made to depend on the fund-raising efforts of sufferers and their families?

Charles is 13. Until two months ago he was hooked on his home computer, playing mindless games for up to 30 hours a week. He's typical of an increasing number of children with a new problem - computer dependency. Like most parents, Charles's mum and dad thought a computer would help him educationally and at first they encouraged him to become computer 'literate'. Now, alarming research indicates that some children, particularly boys, become so entranced with the machine that their psychological and emotional development is affected. They learn to prefer computers to people.

Everyone knows rain forests ought to be saved. But does anyone really know how? One idea comes from a scientist in Scotland: find a plant, growing only in a particular forest, which could be turned into a valuable medicine. The money the drug earned could help the local people so that they would not have to destroy the forest to survive. Professor Peter Waterman 's quest for a cancer-fighting chemical takes him into the heart of Cameroon in Africa to see if he really can help to find a rain forest remedy.

Isn't it crazy that you have to turn off your water supply just to change a tap washer? That installing a simple electric cable involves cutting channels in the wall and then redecorating the room? That we live in the worst insulated houses in northern Europe? Bob Symes is fed up with UK home design, which he believes is hopelessly irrational and out-of-date. He has his own house built, specially for Q.E.D., to prove his point.

Josiah wants to be an actor; Marissa just has to make it as a cheer leader; and as for Scott - well, he just wants to have a happier time. Because, like Josiah and Marissa, he has one obsessive problem - a body that's far too flabby and fat. Camp Shane is where American parents think that they can buy the answer to a problem their kids bought along with too much junk food. But Josiah, Marissa and Scott discover there's more to being thin than buying an instant solution - and Fat Camp, as they call it, may help in ways it never intended.

Every day Charles Tempus catches the 8.10 train to work; regular as clockwork. One morning a boy approaches him on the station platform and asks him the time. That innocent question takes Mr Tempus on a fascinating journey through time - back down the centuries in the days before clocks, and forward into the future via a black hole. On the way Mr Tempus meets young Albert Einstein who introduces him to the mysteries of relativity

As Valentine's Day roses fade and die, take stock of your love-life. Look across the room at your husband, wife or lover and ask, will we be together in two years' time? Dr John Gottman , an American psychologist, claims he can tell you the answer right now. All he needs is a weekend of your time under the scrutiny of the cameras and his tireless staff in the love laboratory.

Wherever we go we leave something unique behind - a faint trace of our own special smell. And that lingering odour is beginning to excite the interest of policemen, who think that smell evidence could help catch criminals. Q.E.D. follows the trail of British scientists working on an electronic nose which detectives could use over here; and discovers that in Holland, your personal BO can already land you behind bars!

Emmett has never been able to walk as well as other children. He has cerebral palsy. When doctors predicted he might soon need a wheelchair, the future looked grim. An American surgeon learned of his plight and offered to help. Within days, 12-year-old Emmett had flown to the United States where they used a special computerised system to pinpoint precisely what had gone wrong. The doctors decided massive surgery might help to put things right. But there were no guarantees. So it was back to the drawing board for Emmett and he was scared. Yet it was his big chance to live like other people - on his own two feet.

Director of music David Hindley has given up the comforts of academic life for the prickly hedges and fields around Cambridge. Why? Because that's where he finds the best composers! Birds live in the fast lane and what sounds like chirrup and tweet to us only reveals its amazing secrets when you slow it all down. David has done just that and transcribed birdsong for the piano. The result is not only new music; it raises deep questions.

A serious look at humour by Jonathan Miller. While helpless with laughter, have you ever wondered why you're in the grip of this strange respiratory convulsion, and what exactly triggered it? There have been many theories about the science of humour, but tonight Dr Miller suggests a few of his own. As doctor, theatre director, philosopher and comedian rolled into one, he has some intriguing and amusing insights into something we all take for granted. But is he right? See if you think he really manages to explain something that's baffled philosophers and psychologists for centuries.

Sheila has to take the decision whether or not to have a brain operation for her depression. She knows there are no guarantees it will work - but it might. More than 20 years ago she was eagerly expecting the birth of a child. The birth was normal but Sheila suffered a severe postnatal depression which eventually progressed to a seemingly incurable deep depression. After many years of enduring every form of treatment, none of which worked, Sheila was offered the last resort - surgery on her brain.

Surrogacy is often seen as a frightening emotional triangle - a rare answer to childlessness fraught with ethical problems. But in Britain, at any one time, some 20 surrogate arrangements are known to be happening. Many are successful and take place in secret. Mark and Rona lost their baby and, in a fight for Rona's life, surgeons removed her womb. Thought too old to adopt, they were determined to have a child and agonized about surrogacy. This special edition of Q.E.D. follows them from the decision to go ahead until the day when the baby was handed over.