Sikkim and Bhutan, 1909

 J. Claude White

Sikkim and Bhutan, 1970

 V.H Coelho

 Himalayan Journal, 1855
Only for aficionados. The first Westerner to travel this corner of the Himalayas was a British botanist. His journals are also available online.

 Joseph Dalton Hooker (Author)

 Gazetter of Sikkim, 1894

 H.H. Risley

 Enchanted Frontiers, 1971

 Nari Rustomji

 India and Tibet, 1910

 Col. Younghusband

 Sikkim the Mountain Kingdom, 1972

 C. Y. Salisbury

 Sikkim, 1873

 J. C. Gawler

 An Expedition to Lhasa 1906

 Col. Younghusband

 Report of a Mission to Sikkim 1885

 Colman Macaulay

The Kangchenjunga Adventure
A hero of early mountaineering describes one of the early expeditions. They attempted Kangchenjunga itself, when defeated climbed lesser peaks. Covers both Nepal and Sikkimese area.

F. S Smythe

 Among the Himalayas 1899
Interesting description by Waddell, one of the first western travelers in Sikkim.

 L. Austin Waddell

 Lands of the Thunderbolt 1923

 Ronald Shay

 Report on the State of Bhutan 1865

 Ashley Eden

 The Jewel in the lotus 1957

 B.J. Gould

 Journey to Lhasa and Central Tibet 1902

 S.C Das

 Sikkim saga 1983

 B. S. Das

 Sikkim: A short Political History 1974

 L. B. Basnet

Report of a visit to Sikkim and Tibetan Frontier 1874

 J. W. Edgar

 Sikkim Coronation 1965

 Coronation Souvenir Book Committee

 Politics of Sikkim 1975

 A. C. Sinha

 Sikkim- A Statistical Profile Bureau of Economics & Statistics.

 State Government and Politics: Sikkim

 N. Sengupta

 An introduction to the History and Religion of Tibet 1991

 N. C. Shah

 Sikkim 1989

 R. Bedi

 Sikkim- Himalayan Rhodendrons

 Udai Pradhan, S. T.Lachungpa

 Birds of Sikkim

 Salim Ali

 The Butterflies of the Sikkim Himalayas

 Meena Haribal

 Medicinal Plants of Sikkim

 L. Rai & E. Sharma

 Perennial Dreams

 Pawan Chamling

 Kanchenjunga The Mountain God

 Col. Narindra Kumar

In the Shadows of the Himalayas
Tibet - Bhutan - Nepal - Sikkim Historic photographic Record of John Claude White 1883-1908, the British "consular" in Sikkim.

Kurt Meyer (Author)
Pamela Deuel Meyer (Collaborator)

 Round Kangchenjunga
A great description of the first trek around the Kangchenjunga massif, starting in Darjeeling then going to North Sikkim and into Nepal (Pangpema), from there over Kang La back to Sikkim, up the Goecha La and then to Yuksom

 Douglas W Freshfield

Trekking in Sikkim and Darjeeling
Bericht über eine 4-wöchige Reise in den Nordosten Indiens (Taschenbuch)
Interesting booklet about a 4 week trek in the area.

 Sacred Summit

 Pema Wangchuk and Mita Zulca

Thirty-seven years of big game shooting in Cooch Behar, the Duars, and Assam.
A rough diary (1908), Book digitized by Google from the library of the New York Public Library and uploaded to the Internet Archive by user tpb.

Nṛipendra Nārāyaṇa Bhūpa, maharajah of Cooch Behār, 1862-1911

'Red with Two Blue Stripes',
The Story of the Indian General Service Medal by Colonel B.A.H.Parritt M.B.E. has a good write up of the Bhotan Duar war campaign, the bonus being it mentions various officers by name and their involvement. Although only 16 (A4) pages on the campaign a very useful insight into what went on.

B.A.H.Parritt