Once again, a thread dedicated to discuss what constitutes for the listener (that's you!) the essence of a specific composer's musical style and language.
It's not easy to choose a particular composer for that kind of finding mission. I will avoid composers who are known almost exclusively for their work in a specific genre, whether they are symphonists (Bruckner, Mahler) or opera composers (Verdi, Puccini, Wagner). A composer who wrote and excelled in many genres can appeal to different layers of musical tastes, different kinds of listeners, and we have more chances for a fruitful discussion.
So, why is
Vaughan-Williams appealing to you? And what work would you consider to epitomize the qualities you seek in his music?
Summary: VW wrote small as well as large-scale works, his oeuvre spans over 6 decades and has from the get go been recognized as that of an accomplished and original composer. He wrote in a resolutely tonal, conservative idiom and he freely borrowed from various traditions. Known for popular orchestral works such as the Fantasia on a Theme of Thomas Tallis, Fantasia on Greesleeves or The Lark Ascending, he also wrote on vast canvases (A Sea Symphony), freely used popular and religious subjects alike, and was a past master at writing for both the orchestra and massed voices.
For a non professional it is hard to pinpoint specifics of his musical language. And yet everybody can recognise a VW work in a mere seconds. His sound world is as surely identifiable as that of his contemporaries Sibelius or Ravel.
My take on 'the essence of Vaughan-Williams': after much hesitation, I went for what may be his most famous work, one that has never been out of the concert halls or recording studios: his magical, haunting, moving and incredibly sophisticated
Fantasia on a Theme of Thomas Tallis.
The Fantasia's instrumentation calls for a full size string section, a smaller string section (single desks only) and a string quartet. The richness and deep sonority of the ensemble is breathtaking. It evokes vastness, timelessness, longing and fulfillment, visions of eternity as well as memories of times long gone. In just 15 minutes this work has the capacity to evoke vast expanses of time as well as space. I find it uniquely evocative.
The Tallis Fantasia shows VW's sophistication as a composer. Many of his works freely incorporate specific instruments as an additional voice (such as the violin in Job), sometimes in an almost concertante role (Flos Campi). With a wealth of amateur and professional choirs available at will throughout England he composed many works for voices. He even indulged in writing the beautiful Serenade to Music for a group of 16 famous soloists of the time. He also wrote many concertos (tuba, violin, piano, oboe), operas, oratorios, ballets, etc. The catholicity of his tastes was astounding. And yet in the Fantasia he restricted himself to one of the most difficult idioms, writing strictly for strings in a langage much indebted to the old viol consorts. Far from sounding academic or scholarly, the work liberates tons of musocal emotions. Its evocative power is unique among strings only works. Strauss in
Metamorphosen chooses to turn inward and evoke mostly negative feelings (sorrow, pain, unresolved tensions, regret, bitterness and, ultimately, death. Vaughan-Williams also evokes some of those feelings, but everything in the end is sublimated by an engulfing feeling of catharsis. When the work ends we have come full circle. Affliction and heartache are left behind, consolation and peacefulness linger gently.
Many other works could be chosen (I'll let you fellow posters do that

). That is a measure of the greatness of a composer I consider among the four or five giants of his century.
Try to 'walk the plank'

and zero in on a specific work, and let us know your thoughts on the music and the composer.