The Astonished Heart is a short play by Noël Coward, one of ten that make up Tonight at 8:30, a cycle written to be performed across three evenings. The play, described at its first production as "a tragedy in six scenes", is told through a series of flashbacks in reverse order. The title is taken from Deuteronomy 28:28, "the Lord shall smite thee with madness and blindness and astonishment of heart."
In the introduction to a published edition of the plays, Coward wrote, "A short play, having a great advantage over a long one in that it can sustain a mood without technical creaking or over padding, deserves a better fate, and if, by careful writing, acting and producing I can do a little towards reinstating it in its rightful pride, I shall have achieved one of my more sentimental ambitions."
The play was first produced in 1935 in Manchester and on tour and played in London (1936), New York (1936–1937) and Canada (1938). It has enjoyed several major revivals and in 1949 was adapted for film. At the London première, The Astonished Heart was played on the same evening as Family Album and Red Peppers. Like all the other plays in the cycle, it originally starred Gertrude Lawrence and Coward himself.
Six of the plays in Tonight at 8:30, including The Astonished Heart, were first presented at the Manchester Opera House beginning on 15 October 1935, and a seventh play was added on the subsequent provincial tour. The final three were added for the London run: Ways and Means, Still Life. The plays were performed in various combinations of three at each performance during the original run. The plays chosen for each performance were announced in advance, although a myth evolved that the groupings were random. Matinées were sometimes billed as Today at 2:30.
On its opening night in Manchester, The Astonished Heart was presented together with We Were Dancing and Red Peppers. The first London performance was on 9 January 1936 at the Phoenix Theatre. Coward directed all ten pieces, and each starred Coward and Gertrude Lawrence. Coward said that he wrote them as "acting, singing, and dancing vehicles for Gertrude Lawrence and myself". Coward loved playing in some of the other plays in Tonight at 8:30, particularly Fumed Oak and Red Peppers, but "I hated playing The Astonished Heart. It depressed me."The Astonished Heart was not one of the best-received plays in Tonight at 8:30 (or Tonight at 7:30 as it was billed in Manchester, to reflect the earlier starting time in the provinces in the 1930s). The Manchester Guardian described it as "a clever play which probably touched nobody's heart", and other reviews said much the same.