| Engels to Friedrich Adolph Sorge. 11 January |
| Engels to Ferdinand Domela Nieuwenhuls. 11 January |
| Engels to Pasquale Martignetti. 18 January |
| Engels to Pasquale Martignetti. 26 January |
| Engels to Florence Kelley-Wischnewetsky. 27 January |
| Engels to Paul Lafargue. 28 January |
| Engels to Laura Lafargue. 2 February |
| Engels to Florence Kelley-Wischnewetsky. 9 February |
| Engels to Friedrich Adolph Sorge. 12 February |
| Engels to Paul Lafargue. 16 February |
| Engels to Nikolai Danielson. 19 February |
| Engels to Laura Lafargue. 24 February |
| Engels to Friedrich Adolph Sorge. 3 March |
| Engels to Friedrich Adolph Sorge. 10 March |
| Engels to Laura Lafargue. 10 March |
| Engels to Julie Bebel. 12 March |
| Engels to Friedrich Adolph Sorge. 16 March |
| Engels to Hermann Schluter. 19 March |
| Engels to Laura Lafargue. 21 March |
| Engels to Gerson Trier. 23 March |
| Engels to Friedrich Adolph Sorge. 6 April |
| Engels to Friedrich Adolph Sorge. 9 April |
| Engels to Paul Lafargue. 11 April |
| Engels to Paul Lafargue. 13 April |
| Engels to Friedrich Adolph Sorge. 23 April |
| Engels to Nikolai Danielson. 24 April |
| Engels to Laura Lafargue. 26 April |
| Engels to Friedrich Adolph Sorge. 4 May |
| Engels to Eduard Bernstein. 5 May |
| Engels to Florence Kelley-Wischnewetsky. 7 May |
| Engels to Friedrich Adolph Sorge. 7 May |
| Engels to Pasquale Martignetti. 21 May |
| Engels to Laura Lafargue. 21 May |
| Engels to Karl Kautsky. 27 May |
| Engels to Eduard Bernstein. 28 May |
| Engels to Florence Kelley-Wischnewetsky. 28 May |
| Engels to Florence Kelley-Wischnewetsky. 31 May |
| Engels to Friedrich Adolph Sorge. 4 June |
| Engels to Laura Lafargue. 7 June |
| Engels to Jules Guesde. 11 June |
| Engels to Laura Lafargue. 11 June |
| Engels to Karl Kautsky. 15 June |
| Engels to Friedrich Adolph Sorge. 18 June |
| Engels to Pasquale Martignetti. 20 June |
| Engels to John Lincoln Mahon. 22 June |
| Engels to John Lincoln Mahon. 23 June |
| Engels to Friedrich Adolph Sorge. 30 June |
| Engels to Laura Lafargue. 15 July |
| Engels to Florence Kelley-Wischnewetsky. 20 July |
| Engels to Karl Kautsky. 22 July |
| Engels to John Lincoln Mahon. 26 July |
| Engels to Karl Kautsky. 1 August |
| Engels to Karl Kautsky. 5 August |
| Engels to Friedrich Adolph Sorge. 8 August |
| Engels to Laura Lafargue. 9 August |
| Engels to August Bebel. 13 August |
| Engels to Karl Kautsky. 17 August |
| Engels to Bruno Schoenlank. 29 August |
| Engels to August Bebel. 30 August |
| Engels to Karl Kautsky. 3 September |
| Engels to Pyotr Lavrov. 3 September |
| Engels to Florence Kelley-Wischnewetsky. 15 September |
| Engels to Friedrich Adolph Sorge. 16 September |
| Engels to Hugo Koeh. 22 September |
| Engels to Johannes Weiss. 10 October |
| Engels to Laura Lafargue. 11 October |
| Engels to Friedrich Adolph Sorge. 29 October |
| Engels to Paul Lafargue. end October |
| Engels to Laura Lafargue. 12 November |
| Engels to Paul Lafargue. 16 November |
| Engels to Paul Lafargue. 22 November |
| Engels to Paul Lafargue. 23 November |
| Engels to Conrad Schmidt. 26 November |
| Engels to Natalle Liebknecht. 29 November |
| Engels to Friedrich Adolph Sorge. November |
| Engels to Florence Kelley-Wischnewetsky. 3 December |
| Engels to Paul Lafargue. 5 December |
| Engels to Hermann Schluter. 7 December |
| Engels to Karl Kautsky. 20 December |
| Engels to Laura Lafargue. 24 December |
| Engels to Paul Lafargue. 29 December |