Publishers
- The Japan Forum 1
- The Jewish Museum 1
- The John C. Winston Company 1
- The John Hopkins Press 1
- The John Hopkins University Press 1
- The Johns Hopkins Press 1
- The Joint Council Of Qualified Opticians 1
- The Jumping Bean Co. 1
- The Junior Institution Of Engineers 1
- The Kemp House Press 1
- The Kennel Club 5
- The Kerryman 1
- The King's England Press 1
- The Kobunsha 1
- The Kylin Press 1
- The Lambourn Press 1
- The Lancashire & Yorkshire Railway Society 5
- The Latymer Foundation 1
- The Law Union and Rock Insurance Company Limited 1
- The Lawrence Wright Music Co. Ltd. 1
- The Le Play Society 1
- The Leicestershire Archaeological And Historical Society 1
- The Library Press Ltd. 2
- The Light Railway Transport League 1
- The Limited Editions Club 1
- The Little Egret Press 4
- The Livingstone Press 1
- The LMS-Patriot Company Ltd. 1
- The London Stamp Exchange 3
- The Lyon Press 1
- The Lyons Press 1
- The Machinery Publishing Co. Ltd. 1
- The Macmillan Co. 1
- The Macmillan Company 10
- The Macmillan Company Of Australia 1
- The Macmillan Company Of Canada Limited 2
- The Macmillan Press Ltd. 1
- The Maharaja Sayajirao University Of Baroda 1
- The Malvern Publishing Company Ltd. 1
- The Malvernian Society 3
- The Manx Experience 4
- The Mathematical Association 1
- The Mathematical Association Of America 1
- The Medici Society 9
- The Medici Society Ltd. 5
- The Medlar Press 8
- The Mendip Press 1
- The Mercat Press 1
- The Mercian Publishers 1
- The Merioneth Historical And Record Society 1
- The Metals Society 1
- The Metropolitan Museum of Art 6
- The Mid Northumberland Arts Group 1
- The Middlesex County Record Society 4
- The Midland Educational Company 1
- The Military Press 1
- The Mining Research Group 2
- The MIT Press 2
- The Modern Art Society Ltd. 1
- The Monmouthshire Golf Club 1
- The Motor World Publishing Co. Ltd. 6
- The Museum of Modern Art 1
- The Museum Of Transport 1
- The National Archives Of India 1
- The National Assembly Of Wales 2
- The National Audubon Society 2
- The National Gallery Of Art, Washington 4
- The National Library of Wales 4
- The National Magazine Co. Ltd. 2
- 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