| Engels to Filippo Turati 7 January |
| Engels to Maria Mendelson 10 January |
| Engels to Philipp Pauli 11 January |
| Engels to Maria Mendelson 16 January |
| Engels to Friedrich Adolph Sorge 18 January |
| Engels to Louis Heritier 20 January |
| Engels to August Bebel 24 January |
| Engels to Maria Mendelson 24 January |
| Engels to Karl Kautsky 26 January |
| Engels to Hermann Engels 26 January |
| Engels to Wilhelm Liebknecht 29 January |
| Engels to Filippo Turati 30 January |
| Engels to Filippo Turati 1 February |
| Engels to Maria Mendelson 7 February |
| Engels to Vladimir Shmuilov 7 February |
| Engels to August Bebel 9 February |
| Engels to Laura Lafargue 12 February |
| Engels to August Bebel 24 February |
| Engels to Nikolai Danielson 24 February |
| Engels to Paul Lafargue 25 February |
| Engels to Laura Lafargue 25 February |
| Engels to Thomas Cook and Son 3 March |
| Engels to Wilhelm Liebknecht 7 March |
| Engels to Filippo Turati 12 March |
| Engels to F. Wiesen 14 March |
| Engels to Laura Lafargue 14 March |
| Engels to Maria Mendelson 15 March |
| Engels to Henry Demarest Lloyd [mid] March |
| Engels to Friedrich Adolph Sorge 18 March |
| Engels to Karl Kautsky 20 March |
| Engels to Laura Lafargue 21 March |
| Engels to August Radimsky 21 March |
| Engels to Julie Bebel 31 March |
| Engels to M. R. Cotar 8 April |
| Engels to George William Lamplugh 11 April |
| Engels to Franz Mehring 11 April |
| Engels to Jules Guesde 14 April |
| Engels to Laura Lafargue 25 April |
| Engels to Ludwig Schorlemmer 29 April |
| Engels to Pablo Iglesias April |
| Engels to Friedrich Adolph Sorge 17 May |
| Engels to Pyotr Lavrov 21 May |
| Engels to Isaac A. Hourwich 27 May |
| Engels to Henry Demarest Lloyd 27 May |
| Engels to Karl Kautsky 1 June |
| Engels to Hermann Bahr [early] June |
| Engels to Filippo Turati 6 June |
| Engels to Giovanni Domanico 7 June |
| Engels to Stojan Nokoff 9 June |
| Engels to Pyotr Lavrov 13 June |
| Engels to Laura Lafargue 20 June |
| Engels to Paul Lafargue 27 June |
| Engels to Paul Lafargue 29 June |
| Engels to Filippo Turati 12 July |
| Engels to Franz Mehring 14 July[alt] |
| Engels to Rudolph Meyer 19 July |
| Engels to Laura Lafargue 20 July |
| Engels to Filippo Turati 20 July |
| Engels to Wilhelm Liebknecht 27 July |
| Engels to Natalie Liebknecht 27 July |
| Engels to Nicolas Petersen 31 July |
| Engels to Ludwig Schorlemmer 31 July |
| Engels to Hermann Engels 16 August |
| Engels to Laura Lafargue 21 August |
| Engels to Emma Engels 23 August |
| Engels to Laura Lafargue 31 August |
| Engels to Laura Lafargue 18 September |
| Engels to Karl Kautsky 25 September |
| Engels to Laura Lafargue 30 September |
| Engels to Engels to Julie Bebel 3 Oct |
| Engels to Hermann Blocher 3 October |
| Engels to John B. Shipley 3 October |
| Engels to Friedrich Adolph Sorge 7 October |
| Engels to Victor Adler 11 October |
| Engels to August Bebel 12 October |
| Engels to Paul Lafargue 13 October |
| Engels to Laura Lafargue 14 October |
| Engels to Nikolai Danielson 17 October |
| Engels to Laura Lafargue 18 October |
| Engels to August Bebel 18 October |
| Engels to Laura Lafargue 27 October |
| Engels to Ferdinand Wolff [end] October |
| Engels to Karl Kautsky 3 November |
| Engels to Victor Adler 10 November |
| Engels to Friedrich Adolph Sorge 11 November |
| Engels to Florence Kelley-Wischnewetsky 11 November |
| Engels to Paul Lafargue 19 November |
| Engels to Natalie Liebknecht 1 December |
| Engels to Friedrich Adolph Sorge 2 December |
| Engels to Hermann Schluter 2 December |
| Engels to Hermann Schluter 2 December |
| Engels to Karl Kautsky 4 December |
| Engels to Paul Arndt 5 December |
| Engels to Laura Lafargue 19 December |
| Engels to Ludwig Schorlemmer 19 December |
| Engels to Adelheid Dworak 21 December |
| Engels to Wilhelm Liebknecht 21 December |
| Engels to Friedrich Adolph Sorge 30 December |