However, I believe that Sassoon is a "neglected poet" when it comes to the poetry that he wrote after the War. Bear in mind that he was born in 1886 and died in 1967 - just short of 81. During most of the 49 years of his life after the War he continued to write poetry, and, although he was certainly a well-known personage, his poetry was generally viewed by critics as out-of-fashion (or, more commonly, was simply ignored).
I readily admit that I, too, viewed him simply as a "War Poet" - until I read Siegfried Sassoon: A Poet's Pilgrimage by D. Felicitas Corrigan (published in 1973). The book combines extracts of Sassoon's writing (some of it previously unpublished) with a biographical narrative that places the pieces in context. I discovered that there was a great deal that I had missed in Sassoon. Here is a small part of what I found.
One winter's end I much bemused my head
In tasked attempts to drive it up to date
With what the undelighting moderns said
Forecasting human fate.
And then, with nothing unforeseen to say
And no belief or unbelief to bring,
Came, in its old unintellectual way,
The first real day of spring.
Sequences (1956). This poem was originally published in 1950 in a volume titled Common Chords.
'When I'm alone' -- the words tripped off his tongue
As though to be alone were nothing strange.
'When I was young,' he said; 'when I was young . . .'
I thought of age, and loneliness, and change.
I thought how strange we grow when we're alone,
And how unlike the selves that meet, and talk,
And blow the candles out, and say good-night.
Alone . . . The word is life endured and known.
It is the stillness where our spirits walk
And all but inmost faith is overthrown.
Collected Poems (1961). According to Sassoon, this poem was written in December of 1924.