The High-Energy Physics (HEP) community spearheaded Open Access with over half a century of dissemination of pre-prints, culminating in the arXiv system. It is now proposing an Open Access publishing model which goes beyond present, sometimes controversial, proposals, with a novel practical approach: the Sponsoring Consortium for Open Access Publishing in Particle Physics (SCOAP3). In this model, libraries and research institutions federate to explicitly cover the costs of the peer-review and other editorial services, rather than implicitly supporting them via journal subscriptions. Rather than through subscriptions, journals will their costs from SCOAP3 and make the electronic versions of their journals free to read. Unlike many “author-pays” Open Access models, authors are not directly charged to publish their articles in the Open Access paradigm. Contributions to the SCOAP3 consortium are determined on a country-by-country basis, according to the volume of HEP publications originating from each country. They would come from nation-wide re-directions of current subscriptions to HEP journals. SCOAP3 will negotiate with publishers in the field the price of their peer review services through a tendering process. Journals converted to Open Access will be then decoupled from package licenses. The global yearly budget envelope for this transition is estimated at about 10 Million Euros. This unique experiment of “flipping” from Toll Access to Open Access all journals covering the literature in a given subject is rapidly gaining momentum, and about a third of the required budget envelope has already been pledged by leading libraries, library consortia and High-Energy Physics funding agencies worldwide. This conference paper describes the HEP publication landscape and the bibliometric studies at the basis of the SCOAP3 model. Details of the model are provided and the status of the initiative is presented, debriefing the lessons learned in this attempt to achieve a large-scale conversion of an entire field to Open Access.