Profile: Professor Peter Higgs of Higgs boson fame
In the 1960s, the British physicist Professor Peter Higgs predicted the existence of the so-called "God Particle", which scientists working at the Large Hadron Collider at the European Organization for Nuclear Research (CERN) believe they are on the verge of identifying.
Also known as the Higgs boson, it is a subatomic particle which gives mass to all matter and the quest to find it has been described as the holy grail of physics.
Peter Higgs made his prediction as a relatively young scientist, adding a crucial element to the Standard Model of the universe - which sets out to explain what the universe is made of.
At the time, the significance of his work was not widely recognised or understood, and one leading scientific journal even turned down one of his early papers setting out the ground-breaking theory.
Higgs, now in his 80s, is very much a theoretical scientist. Colleagues say he has never excelled at practical experiments, and to this day he does not get on well with computers.
Samira Ahmed talks to those who know him well, and asks what makes him tick.
Profile, external was broadcast on BBC Radio 4 on Saturday, 17 December at 19:00 GMT. Listen again via the Radio 4 website, external or download the Profile Podcast, external.