Publishers
- The National Sunday School Union 2
- The National Traction Engine Club Ltd. 1
- The National Trust 2
- The National Trust For Scotland 1
- The Natural History Press 1
- The Natural History Society Of Northumbria 1
- The Natural Science Association Of America 1
- The Naval & Military Press Ltd. 5
- The Nettlebed Press 1
- The New American Library 1
- The New-York Historical Society 1
- The Newcomen Society 2
- The Newport Printing Co. 3
- The Newstead Press 1
- The Nonesuch Press 2
- The North Eastern Railway Association 6
- The Northern Publishing Co. Ltd. 1
- The O'Brien Press Ltd. 3
- The Oakwood Press 48
- The Old Felstedian Society 2
- The Old Leysian Union 1
- The Old Monmothian Club 1
- The Old Pauline Club 1
- The Old Rugbeian Society 1
- The Old School Press 1
- The Original Double Red Ltd. 2
- The Ornithological Society Of Japan 1
- The Owl Press Ltd. 1
- The Oxford Illustrated Press 4
- The Packard Humanities Institute 1
- The Paddle Steamer Preservation Society 1
- The Page Company 1
- The Paternoster Press Ltd. 1
- The Paterson Engineering Co. Ltd. 1
- The Paul Mellon Foundation For British Art 1
- The Penguin Group 17
- The Penn Publishing Company 1
- The Pennsylvania State University Press 1
- The Pentland Press 4
- The Peppertree Press 1
- The Pequot Press 1
- The Perth Printing Company 1
- The Pet Book Publishing Company Limited 1
- The Physical Society 1
- The Pierpont Morgan Library 1
- The Pilgrim Press 4
- The Pilgrim Press Limited 1
- The Pilot Press Ltd. 1
- The Plane Picture Co. Publishing 2
- The Platt And Munk Co. Inc. 2
- The Porcupine's Quill 1
- The Port Of Bristol Authority 1
- The Pragmatic Bookshelf 2
- The Pre-War Austin Seven Club Ltd. 1
- The Provincial Grand Lodge Of Middlesex 1
- The R.S. Surtees Society 1
- The R.T.S. Office 2
- The Radcliffe Press 3
- The Raf Cranwell Aircraft Apprentices Association 2
- The Railway Correspondence And Travel Society 41
- The Railway Gazette 1
- The Railway Publishing Co. Ltd. 4
- The Ranelagh Press 1
- The Ray Society London 3
- The Readers Library Publishing Co. Ltd. 1
- The Rector Of Jarrow 1
- The Regensteiner Corporation 1
- The Regimental Trust 10th Princess Mary's Own Gurkha Rifles 1
- The Reilly & Britton Co. 1
- The Religious Tract Society 18
- The Richards Press 4
- The Richards Press Ltd. 21
- The Richmond Publishing Co. Ltd. 1
- The Rifle Brigade Club And Association 1
- The Rissingtons Local History Society 1
- The Rockingham Press 2
- The Rolls House Publishing Co., Ltd. 1
- The Ronald Press Company 2
- The Royal Air Force 1
- The Royal Anthroplogical Institute Of Great Britain And Ireland 2
- The Royal Commission on Ancient and Historical Monuments in Wales 2
- The Royal Commission On The Ancient And Historical Monuments Of Scotland 1
- The Royal Green Jackets Museum Trust 1
- The Royal Historical Society 4
- The Royal Institute of British Architects 2
- The Royal Society 3
- The Royal Statistical Society 1
- The Royal Swedish Commission 2
- The Rubicon Press 2
- The Saalfield Publishing Company 3
- The Sabah Society 1
- The Salmon And Trout Association 1
- The Saturn Press 1
- The Scientific Book Club 1
- The Scientific Publishing Co. 1
- The Scottish Railway Preservation Society 1
- The Scout Association 2
- The Self Publishing Association Ltd. 6
- The Sheldon Press 7
- The Shoe Lane Publishing Co. 1