Henry Valentine Knaggs (14 February 1859 – 11 July 1954) was an English doctor and author who was a notable practitioner of nature cure methods (now called Naturopathic medicine).
He was the second son of Henry Guard Knaggs and Ellen Mares. He was born on 14 February 1859 (St Valentine's Day) in St Pancras, London, and there is no evidence that he was ever baptised.
Like his father and grandfather before him, he embarked on a medical career. There is no evidence of an apprenticeship but he obtained his LSA in 1881 after studying at University College London. He was awarded his MRCS and his LM in the same year and also an LRCP from the University of Edinburgh. In 1889 he is recorded as being a Fellow of the Zoological Society.
He worked in the service of the Peninsular and Oriental Steamship Company from 1883 to 1886 presumably on their liners. In 1889 he was resident surgeon at Boscombe Infirmary but his address, from 1883 until 1912 was 189 Camden Road, London NW where he was in general practice as a doctor.
He married Mabel Emily Stow on 24 June 1897 at St Paul's Church, St Pancras – Mabel's father James was just described as "gentleman" on the marriage certificate. They had two daughters – Dulcie (born 1901, who married George Menzies Trevor Lambrick (an officer in the Indian Army) 1929 in Witney), and Nora (born 1902, who married John B. Maxwell 1929 in Hatfield).
The 1913 Medical Who's Who gives Knaggs' addresses as 41 Welbeck Street and Combe Edge, Langley Park, Mill Hill. In 1914 he was living at 41 Queen Anne Street, then, to 1921 (and probably later) he was practising from the up-market address of 25 Wimpole Street, but he was living at "Arbor", Kings Langley in rural Hertfordshire. His specialities were listed as electro-therapeutics, dietetics and haematology, and his recreations as athletics and literary work of various kinds.