Sources: CtY-BR
- Samuel L. Clemens to Francis Bret Harte, 1 May 1867 · New York, N.Y · UCCL00128
- Samuel L. Clemens to Frank Fuller, 7 August 1867 · Naples, Italy · UCCL00142
- Samuel L. Clemens to Frank Fuller, 5 December 1867 · Washington, D.C · UCCL00170
- Samuel L. Clemens to Joseph H. and Harmony C. Twichell, 18 November 1868 · Cleveland, Ohio · UCCL02765
- Samuel L. Clemens to Francis E. Bliss, 7 January 1869 · Chicago, Ill · UCCL00221
- Samuel L. Clemens to Harriet Lewis, 10 January 1869 · Galesburg, Ill · UCCL00226
- Samuel L. Clemens to Elisha Bliss, Jr., 15 April 1869 · Elmira, N. Y · UCCL00283
- Samuel L. Clemens to Elisha Bliss, Jr., 22 July 1869 · Elmira, N.Y · UCCL00327
- Samuel L. Clemens to Joseph H. Twichell, 28 December 1869 · New York, N.Y · UCCL00395
- Samuel L. Clemens to John Fuller, 8 February 1870 · Buffalo, N.Y · UCCL00421
- Samuel L. Clemens to Elisha Bliss, Jr., per Olivia L. Clemens, with revisions by Samuel L. Clemens, 30 May 1870 · Buffalo, N.Y · UCCL00473
- Samuel L. Clemens to Joseph H. and Harmony C. Twichell, 12 November 1870 · Buffalo, N.Y · UCCL00533
- Samuel L. Clemens to Elisha Bliss, Jr., 22 November 1870 · Buffalo, N.Y · UCCL00542
- Samuel L. Clemens to Joseph H. Twichell, 19 December 1870 · Buffalo, N.Y · UCCL02783
- Samuel L. Clemens to A. Francis Judd, 20 December 1870 · Buffalo, N.Y · UCCL02784
- Samuel L. Clemens to John R. Drake, 26 December 1870 · Buffalo, N.Y · UCCL02789
- Samuel L. Clemens to John Henry Riley, 27 March 1871 · Elmira, N.Y · UCCL00597
- Samuel L. Clemens to Elisha Bliss, Jr., 21 March 1872 · Elmira, N. Y · UCCL00738
- Samuel L. Clemens to Francis E. Bliss, 15 May 1872 · Elmira, N. Y · UCCL00749
- Samuel L. Clemens to Elisha Bliss, Jr., 7 August 1872 · New Saybrook, Conn · UCCL00787
- Samuel L. Clemens to The Editor of the Literary World, December 1872 · Hartford, Conn · UCCL00836
- Samuel L. Clemens to Joseph L. Twichell, 20–22 December · Hartford, Conn · UCCL00848
- Samuel L. Clemens to Elisha Bliss, Jr., 25 February 1873 · Hartford, Conn · UCCL00875
- Samuel L. Clemens to Willard M. White, 3 March 1873 · Hartford, Conn · UCCL00880
- Samuel L. and Olivia L. Clemens to Joseph H. Twichell, 29 June 1873 · London, England · UCCL00936
- Samuel L. Clemens to Joaquin Miller, 5 July 1873 · London, England · UCCL00945
- Samuel L. Clemens to Elisha Bliss, Jr. per Samuel C. Thompson, 16 July 1873 · London, England · UCCL00953
- Samuel L. Clemens to Charles Dudley Warner, per Samuel C. Thompson, 16 July 1873 · London, England · UCCL00954
- Samuel L. Clemens to T. B. Pugh, 27 July 1873 · Edinburgh, Scotland · UCCL00957
- Samuel L. Clemens to Elisha Bliss, Jr., 27 July 1873 · Edinburgh, Scotland · UCCL00956
- Samuel L. Clemens to Louisa P. MacDonald, 29 September 1873 · 2nd of 2 · London, England · UCCL11830
- Samuel L. Clemens to James Redpath, 13 February 1874 · Hartford, Conn · UCCL02450
- Samuel L. Clemens to John Brown, 28 February 1874 · Hartford, Conn · UCCL01056
- Samuel L. Clemens to Elisha Bliss, Jr., 22 May 1874 · Elmira, N. Y · UCCL01093
- Samuel L. Clemens to Joseph H. and Harmony C. Twichell, 11 June 1874 · Elmira, N.Y · UCCL01097
- Samuel L. Clemens to Joseph H. Twichell, 29? July 1874 · Elmira, N.Y · UCCL01113
- Samuel L. Clemens to William Dean Howells, 13 November 1874 · New Boston, Conn · UCCL01167
- Samuel L. Clemens to Densmore, Yost and Company, 19 March 1875 · Hartford, Conn · UCCL01212
- Samuel L. Clemens to James R. Osgood, 20 July 1875 · Hartford, Conn · UCCL01251
- Samuel L. Clemens to Joseph H. Twichell, 29 or 30 December 1875 · Hartford, Conn · UCCL01291
- Samuel L. Clemens to Elisha Bliss, Jr., 19 March 1876 · Hartford, Conn · UCCL01315
- Samuel L. Clemens to Elisha Bliss, Jr., 17? April 1876 · Hartford, Conn · UCCL01322
- Samuel L. Clemens to Elisha Bliss, Jr., 24 June 1876 · Elmira, N.Y · UCCL01345
- Samuel L. Clemens to Lewis Jacob Cist, 1 August 1876 · Elmira, N.Y · UCCL01353
- Samuel L. Clemens to Bayard Taylor, 24 January 1877 · Hartford, Conn · UCCL01403
- Samuel L. Clemens to Joseph H. Twichell, 27 June 1877 · Elmira, N.Y · UCCL01444
- Samuel L. Clemens to George Haven Putnam, 16 March 1878 · Hartford, Conn · UCCL01544
- Samuel L. Clemens to Joseph H. Twichell, 10 April 1878 · Elmira, N.Y · UCCL01554
- Samuel L. Clemens to Charles Dudley Warner, 1? August 1878 · Baden Baden?, Germany · UCCL01581
- Samuel L. and Olivia L. Clemens to Joseph H. Twichell, 9 September 1878 · Geneva, Switzerland · UCCL02800
- Samuel L. Clemens to Joseph H. Twichell, 3 November 1878 · Rome, Italy · UCCL01603
- Samuel L. Clemens to Joseph H. Twichell and Susan L. Warner, 20 November 1878 · Munich, Germany · UCCL01608
- Samuel L. Clemens to Joseph H. Twichell, 23 January 1879 · Munich, Germany · UCCL01624
- Samuel L. Clemens to Joseph H. Twichell, 10 June 1879 · Paris, France · UCCL01666
- Samuel L. Clemens to Joseph H. Twichell, 2 October 1879 · Elmira, N.Y · UCCL01696
- Samuel L. Clemens to Joseph Blackburn Jones, 7 November 1879 · Hartford, Conn · UCCL01710
- Samuel L. Clemens to Joseph H. Twichell, 16 March 1880 · Hartford, Conn · UCCL01771
- Samuel L. Clemens to Elisha Bliss, Jr., 21 April 1880 · Hartford, Conn · UCCL01788
- Samuel L. Clemens to Miss Perkins, 30 April 1880 · Hartford, Conn · UCCL01796
- Samuel L. Clemens to Unidentified, June 1880 · Hartford, Conn · UCCL11048
- Samuel L. Clemens to Joseph H. Twichell, per Telegraph Operator, 14 October 1880 · Boston, Mass · UCCL01841
- SLC to Unidentified, May 1881 · Hartford, Conn · UCCL09314
- SLC to Osgood (J.R.) & Co., 2 July 1881 · Branford, Conn · UCCL01980
- SLC to Benjamin H. Ticknor, 1 August 1881 · Branford, Conn · UCCL01992
- SLC to Benjamin H. Ticknor, 11 August 1881 · Elmira, N.Y · UCCL02000
- SLC to Benjamin H. Ticknor, 14 August 1881 · Elmira, N.Y · UCCL02006
- SLC to James R. Osgood, 21 October 1881 · Hartford, Conn · UCCL02058
- SLC to Joseph H. Twichell, 18? February 1882 · Hartford, Conn · UCCL02132
- SLC to Andrew Chatto, 3 March 1882 · Hartford, Conn · UCCL02169
- SLC to James R. Osgood, 19 July 1882 · Elmira, N.Y · UCCL02238
- SLC to Joseph H. Twichell, 19 September 1882 · Elmira, N.Y · UCCL02271
- SLC to George MacDonald, 19 September 1882 · Elmira, N.Y · UCCL02270
- SLC to James R. Osgood, 15 January 1883 · Hartford, Conn · UCCL02334
- SLC to American Publishing Co., 17 May 1883 · Hartford, Conn · UCCL02387
- SLC to Karl Gerhardt and Hattie J. Gerhardt, 4 May 1884 · Hartford, Conn · UCCL02969
- SLC to Joseph H. Twichell, 16 September 1884 · Elmira, N.Y · UCCL01327
- SLC to Charles L. Webster, 23 November 1884 · New York, N.Y · UCCL03036
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