| Engels to Eduard Bernstein. 1 January |
| Engels to Karl Kautsky. 9 January |
| Engels to Laura Lafargue. 14 January |
| Engels to August Bebel. 18 January |
| Engels to August Bebel. 23 January |
| Engels to Charles Fitzgerald. 27 January |
| Engels to Eduard Bernstein. 28 January |
| Engels to Ludwig Krzywicki. 28 January |
| Engels to Pyotr Lavrov. 28 January |
| Engels to Karl Kautsky. 4 February |
| Engels to Eduard Bernstein. 5 February |
| Engels to Pyotr Lavrov. 5 February |
| Engels to Laura Lafargue. 5 February |
| Engels to Heinrich Nonne. 21 February |
| Engels to Johann Philipp Becker. 14 February |
| Engels to Pyotr Lavrov. 14 February |
| Engels to Karl Kautsky. 16 February |
| Engels to Laura Lafargue. 16 February |
| Engels to John Darbyshire. c. 17 February |
| Engels to Laura Lafargue. 21 February |
| Engels to Heinrich Nonne. c. 26 February |
| Engels to Karl Kautsky. 3 March |
| Engels to Pyotr Lavrov. 3 March |
| Engels to Vera Zasulich. 6 March |
| Engels to Friedrich Adolph Sorge. 7 March |
| Engels to Paul Lafargue. 11-15 March |
| Engels to Eduard Bernstein. 24 March |
| Engels to Karl Kautsky. 24 March |
| Engels to Laura Lafargue. 31 March |
| Engels to Karl Kautsky. 11 April |
| Engels to Eduard Bernstein. 11 April |
| Engels to Laura Lafargue. 18 April |
| Engels to Paul Lafargue. 18 April |
| Engels to Karl Kautsky. 22 April |
| Engels to Karl Kautsky. 26 April |
| Engels to Ludwig Kugelmann. 4 May |
| Engels to Paul Lafargue. 10 May |
| Engels to Eduard Bernstein. 17 May |
| Engels to Eduard Bernstein and Karl Kautsky. 22 May |
| Engels to Karl Kautsky. 23 May |
| Engels to Eduard Bernstein. 23 May |
| Engels to Laura Lafargue. 26 May |
| Engels to Eduard Bernstein. 5 June |
| Engels to August Bebel. 6 June |
| Engels to Johann Philipp Becker. 20 June |
| Engels to Karl Kautsky. 21-22 June |
| Engels to Karl Kautsky. 26 June |
| Engels to Evgenia Papritz. 26 June |
| Engels to Eduard Bernstein. 29 June |
| Engels to Sarah Allen. About 6 July |
| Engels to Gabriel Deville. 8 July |
| Engels to Karl Kautsky. 11 July |
| Engels to Karl Kautsky. 19 July |
| Engels to Laura Lafargue. 22 July |
| Engels to Eduard Bernstein. c. 25 July |
| Engels to Laura Lafargue. 26 July |
| Engels to Hermann Schluter. 28 July |
| Engels to James Leigh Joynes. 30 July |
| Engels to Eduard Bernstein. 31 July |
| Engels to Laura Lafargue. 1 August |
| Engels to Karl Kautsky. 1 August |
| Engels to Eduard Bernstein. 6 August |
| Engels to Laura Lafargue. 6 August |
| Engels to Paul Lafargue. c. 11 August |
| Engels to Georg Heinrich von Vollmar. 13 August |
| Engels to Marya Jankowska (S Leonowicz). Mid-August |
| Engels to Karl Kautsky. 22 August |
| Engels to Eduard Bernstein. 22 August |
| Engels to Karl Kautsky. 30 August |
| Engels to Eduard Bernstein. 13-15 Sept. |
| Engels to Karl Kautsky. 20 September |
| Engels to Hermann Schluter. 1 October |
| Engels to Hermann Schluter. 3 October |
| Engels to August Bebel. 11 October |
| Engels to Karl Kautsky. 13 October |
| Engels to Johann Philip Becker. 15 October |
| Engels to Karl Kautsky. 15 October |
| Engels to Karl Kautsky. 17 October |
| Engels to Karl Kautsky. 20 October |
| Engels to Eduard Bernstein. 22 October |
| Engels to Eduard Bernstein. 23 October |
| Engels to August Bebel. 29 October |
| Engels to Karl Kautsky. 8 November |
| Engels to Pasquale Martignetti. 8 November |
| Engels to Eduard Bernstein. 11 November |
| Engels to Hermann Engels. 11 November |
| Engels to August Bebel. 18 November |
| Engels to Laura Lafargue. 23 November [abstract] |
| Engels to John Lincoln Mahon. 28 November |
| Engels to Charlotte Engels. 1 December |
| Engels to Karl Kautsky. 9 December |
| Engels to August Bebel. 11 December |
| Engels to Paul Lafargue. Mid-December |
| Engels to Eduard Bernstein. 29 December |
| Engels to Wilhelm Liebknecht. 29 December |
| Engels to August Bebel. 30 December |
| Engels to Pasquale Martignetti. 30 December |
| Engels to Friedrich Adolph Sorge. 31 December |
| Engels to Joseph Dietzgen. 31 December |