Karl Louis, FRPSL, Germany (Special thanks are due to Karl for making the relevant records in his remarkable card index available to me.)
Simon Andrews, London
Ken Baker, Cavendish Auctions
Seymour Banchik, FRPSL, New York, USA
Bill Barrell, Lincolnshire
Maxine Barrow, Leicester
David Beech, FRPSL, The British Library
Bill Bird, Buckinghamshire
John Bohn, FRPSL, London
David Boyd, Phillips, London
Graham Childs, Harmers of London
Andrew Claridge, Essex
Stanley F. Cohen, FRPSL, Spain
R. C. E. Compton, Sussex
V. B. Crookes, Watford
Harry Dagnall, FRPSL, Middlesex
Robert Danzig, Isle of Wight
Derek Deadman, Leicester
David Feldman, Geneva
John Forbes-Nixon, FRPSL, Bristol
D. Forbes-Smith, Bristol
Dr Bob Grafton, Washington, USA
James Grimwood-Taylor, Cavendish Auctions
Alex Harris, New Zealand
Kenneth G. Higgs, Sussex
Nicky Hillman, London
Dr Alan K. Huggins, MBE, RDP, FRPSL, Hertfordshire
David Holl, Jersey
Michael Jackson, Huntingdon
Dr Chris Jarvis, FRPSL, Cornwall
Col. P. H. M. Jefferies, Worcestershire
Andrew Lajer, Berkshire
Gavin Littaur, London
Malcolm G. Lowe, FRPSL, California, USA
The late Robson Lowe, Bournemouth
Don Madden, Spain
Geoff Mansell, Leicestershire
Graham Mark, FRPSL, Somerset
W. de L. M. Messenger, Daventry
Peter Mollett, Ringwood
Douglas N. Muir, FRPSL, The National Postal Museum
David Rowse, FRPSL, London
Arthur Ryan, Surrey
Michael Sefi, FRPSL, Sussex
Lt.-Col. Thomas Slemons, FRPSL, Indiana, USA
Peter Slot, Peter Tarquin (1840) Ltd, Surrey
David Spragg, Buckinghamshire
Vivien Sussex, Yorkshire
Richard Watkins, Spink, London
The late Martin Willcocks, London
Winston Williams, London

The following items are reproduced by gracious permission of Her Majesty The Queen: Penny Black: 5 May AB; 6 May NK; 7 May KK 1; 8 May QA. Penny Mulready: 2 May A65; 6 May A7 2, X2; 7 May X2. Twopenny Mulready: 23 May a92.

The following items are reproduced courtesy of The British Library: Penny Black: 6 May AK; 9 May AD. Adhesive/Mulready combination: 15 May 1d Mulready/Penny Black EC. Penny Mulready: 2 May A34; 4 May A158; 6 May A17 6, A34, A149 3, U12; 10 May A5 1, A189. Twopenny Mulready: 6 May a91, a198.

The following items are reproduced courtesy of the National Postal Museum: Penny Black: 6 May SC 2, TG 1; 10 May HK 2. Adhesive/Mulready combination: 8 May 1d Mulready A34/Penny Black SL. Caricature: 31 May Foresís No. 1/Penny Black TE. Penny Mulready: 1 May A156; 6 May A4, A69 1, A153 3.

While every endeavour has been made to obtain permission to reproduce the illustrations, the source of some of them may inadvertently not have been acknowledged, for which the author apologises.