Maer gyfrol hon yn cynnwys golygiadau o gywyddau gan Iolo Goch, Gruffudd Llwyd, Rhys Goch Eryri, Llywelyn ab y Moel, Siôn Cent, Sypyn Cyfeiliog, Iorwerth ab y Cyriog, Ieuan ap Rhydderch a Ieuan Waed Da. Beirdd yr Uchelwyr or 15g ydyr beirdd hyn i gyd. Ar un adeg roedd y gyfrol yn olygiad safonol o waith y beirdd hyn ond bellach mae golygiadau diweddarach ar gael, sef golygiad yr Athro Dafydd Johnston o Waith Iolo Goch ar gyfres newydd Cyfres Beirdd yr Uchelwyr.
Ceir rhagymadrodd, golygiadau o waith y beirdd unigol wediu trefnu dan eu henwau, nodiadau, geirfa a mynegai.
Edward Williams, better known by his bardic name Iolo Morganwg (1747 - 1826), was a Welsh antiquarian, poet and collector of ill repute. He was seen as an expert collector of Medieval Welsh literature, but it emerged after his death that he had forged several manuscripts, notably some of the Third Series of Welsh Triads. Even so, he had a lasting impact on Welsh culture, notably in founding the secret society known as the Gorsedd, through which Iolo Morganwg successfully coopted the 18th-century Eisteddfod revival. The philosophy he spread in his forgeries has had an enormous impact upon neo-Druidism. His bardic name is Welsh for "Iolo of Glamorgan".