| Engels to Mrs Zadek. c. 1 January |
| Engels to Sergey Stepniak. 3 January |
| Engels to Laura Lafargue. 8 January |
| Engels to Hermann Engels. 9 January |
| Engels to Hermann Schluter. 11 January |
| Engels to Pasquale Martignetti. 13 January |
| Engels to Eleanor Marx-Aveling. 14 January |
| Engels to Hermann Schluter. 15 January |
| Engels to Charles Rosher. 19 January |
| Engels to August Bebel. 23 January |
| Engels to Friedrich Adolph Sorge. 8 February |
| Engels to August Bebel. 17 February |
| Engels to Laura Lafargue. 26 February |
| Engels to Paul Lafargue. 7 March |
| Engels to Wilhelm Liebknecht. 9 March |
| Engels to Laura Lafargue. 14 March |
| Engels to Antonio Labriola. 30 March |
| Engels to Pasquale Martignetti. 30 March |
| Engels to Karl Kautsky. 1 April |
| Engels to Johann Heinrich Wilhelm Dietz. 1 April |
| Engels to Vera Zasulich. 3 April |
| Engels to Friedrich Adolph Sorge. 4 April |
| Engels to Ferdinand Domela Nieuwenhuis. 9 April |
| Engels to Karl Kautsky. 11 April |
| Engels to Friedrich Adolph Sorge. 12 April |
| Engels to Conrad Schmidt. 12 April |
| Engels to Laura Lafargue. 16 April |
| Engels to Vera Zasulich. 17 April |
| Engels to Friedrich Adolph Sorge. 19 April |
| Engels to Friedrich Adolph Sorge. 30 April |
| Engels to August Bebel. 9 May |
| Engels to Laura Lafargue. 10 May |
| Engels to Paul Lafargue. 21 May |
| Engels to Pasquale Martignetti. 24 May |
| Engels to Friedrich Adolph Sorge. 29 May |
| Engels to Paul Ernst. 5 June |
| Engels to Nikolai Danielson. 10 June |
| Engels to Hermann Schluter. 14 June |
| Engels to Wilhelm Liebknecht. 19 June |
| Engels to Natalie Liebknecht. 19 June |
| Engels to Ludwig Kugelmann. 30 June |
| Engels to Wilhelm Liebknecht. 30 June |
| Engels to Laura Lafargue. 4 July |
| Engels to Hermann Engels. 8 July |
| Engels to Wilhelm Liebknecht. 22 July |
| Engels to Friedrich Adolph Sorge. 30 July |
| Engels to Laura Lafargue. 30 July |
| Engels to Wilhelm Liebknecht. 1 August |
| Engels to Johann Heinrich Wilhelm Dietz. 5 August |
| Engels to Karl Kautsky. 5 August |
| Engels to Conrad Schmidt. 5 August |
| Engels to Friedrich Adolph Sorge. 9 August |
| Engels to Wilhelm Liebknecht. 10 August |
| Engels to Wilhelm Liebknecht. 15 August |
| Engels to Otto von Boenigk. 21 August |
| Engels to Friedrich Adolph Sorge. 27 August |
| Engels to Paul Lafargue. 27 August |
| Engels to Paul Lafargue. 15 September |
| Engels to Karl Kautsky. 18 September |
| Engels to Paul Lafargue. 19 September |
| Engels to Charles Caron. 20 September |
| Engels to Paul Lafargue. 20 September |
| Engels to Joseph Bloch. 21 September
[alt] |
| Engels to Hermann Engels. 22 September |
| Engels to Jakins. 23 September |
| Engels to Strutt and Parker. 23 September |
| Engels to Jules Guesde. 25 September |
| Engels to Laura Lafargue. 25 September |
| Engels to Paul Lafargue. 25 September |
| Engels to Laura Lafargue. 26 September |
| Engels to Friedrich Adolph Sorge. 27 September |
| Engels to Friedrich Adolph Sorge. 4 October |
| Engels to Karl Kautsky. 5 October |
| Engels to Wilhelm Liebknecht. 7 October |
| Engels to Friedrich Adolph Sorge. 18 October |
| Engels to Laura Lafargue. 19 October |
| Engels to Eduard Bernstein. 20 October |
| Engels to Wilhelm Liebknecht. 25 October |
| Engels to Conrad Schmidt. 27 October
[alt] |
| Engels to Paul Lafargue. 2 November |
| Engels to Friedrich Adolph Sorge. 5 November |
| Engels to Karl Kautsky. 5 November |
| Engels to Louise Kautsky. 9 November |
| Engels to Adolf Riefer. 12 November |
| Engels to Victor Adler. 15 November |
| Engels to Victor Adler. 17 November |
| Engels to Friedrich Adolph Sorge. 26 November |
| Engels to Laura Lafargue. 1 December |
| Engels to Ferdinand Domela Nieuwenhuis. 3 December |
| Engels to Amand Goegg. 4 December |
| Engels to Ludwig Schorlemmer. 4 December |
| Engels to Edouard Vaillant. 5 December |
| Engels to Pyotr Lavrov. 5 December |
| Engels to Wilhelm Liebknecht. 8 December |
| Engels to Mohrhenn. 9 December |
| Engels to Victor Adler. 12 December |
| Engels to Johann Heinrich Wilhelm Dietz. 13 December |
| Engels to Karl Kautsky. 13 December |
| Engels to Laura Lafargue. 17 December |
| Engels to Wilhelm Liebknecht. 18 December |
| Engels to Friedrich Adolph Sorge. 20 December |
| Engels to Leo Frankel. 25 December |
| Engels to G Blume. 27 December |
| Engels to Georg Schumacher. December |