This third edition is the first volume of a two-volume set to North Wales: The Mountain Crags. The bouldering scene in North Wales is now more vibrant and energised than it has ever been. Each year exciting new crags are revealed and the development of existing crags is greatly expanded. The rapid pace of development in recent years has meant a corresponding increase in the guidebook page count. There is now too much material to fit it all in one book, so a split into separate volumes has become necessary. The most logical split is between the inland mountain crags of Eryri and the coastal crags of Pen Llyn, Ynys Mon and Llandudno (plus the North East limestone crags). Volume 2: Coastal Crags and North East Limestone will be published later in 2021. Improvements, additions, updatesBrilliant new areas, such as Llyn Ogwen, Cwm Craig-las and Castell Cidwm have been added to the roster. Existing areas, such as Creigiau'r Garth, Cwm Dulyn, Fachwen and Clegir have seen extensive new development. Superb new lines have been discovered, often in the least likely of places. There has been much improvement to existing descriptions, approach notes, topos and maps. The crag assessment table makes choosing your crag for the day much easier. Grades and star ratings have been tweaked, broken holds and changes noted. There's an epic graded list and a full index. There is also a new wave of inspiring action shots fleshing out the pages, plus the usual professional design quality you can expect from Ground Up. This is certainly a better, more intensely researched book than the previous ones. Simon Panton is the main author and editor of the book, but crucial support has come from key activists, such as Pete Robins, Martin Crook, George Smith, Owen Hayward, Chris Doyle, Tim Peck, Craig Davies and Andy Godber. There has also been a broader feedback group composed of various members of the North Wales climbing scene.