Spent a bit of time listing my Spider book collection, I think it's an addiction. Fortunately I just need
Spiders of Gt. Britain and Ireland part 2 by Blackwall or a combined copy of both volumes and I'll stop (probably!)

.
I had a similar problem with microscopes but I'm cured of that now.
I always thought they'd be pretty cheap when I first started buying them, how wrong was I! for
limited interest -
read specialised topic!
.
•American Spiders – Gertsch (2 copies)
•A Natural History of Spiders and Other Curious Insects – Eleazar Albin (1726)
•A Complete Guide to Tarantulas - A. David
•A Guide to Spiders of Britain and Northern Europe – Dick Jones
•A Guide to Common Singapore Spiders - J. K. H. Koh
•African Spiders – An Identification Manual – A.S. Dippenaar-Schoeman/R. Jocque
•All about Australian Spiders – Ure Smith
•Amazing Spiders - A. Parsons
•Arachnology – Symposia of the Zoological Society of London 1978
•Australian Spiders - J. Child
•Australian Spiders - R. Mascord
•Australian Spiders and their Allies – Walter W. Froggatt 1935 (Signed copy)
•Baboon and Trapdoor Spiders of S. Africa – An identification Manual - A.S. D-Schoeman
•Biology of Spiders – Foelix
•British Spiders (Fieldgap) – L. M. jones-Walters
•British Spiders, Their Lives, Loves & Tragedies - E. C. Ash (2 copies)
•British Spiders – Their Haunts and Habits – T. H. Savory
•British Spiders Vol. I - Lockett & Millidge (1951 1st Edition)
•British Spiders Vol. II - Lockett & Millidge (1953 1st Edition) 2 copies
•British Spiders Vol. III - Lockett, Millidge & Merrett (1974 1st Ed) 2 copies
•British Spiders Vol. I - Lockett & Millidge (1968 Edition)
•British Spiders Vol. II - Lockett & Millidge (1968 Edition)
•British Spiders - Savory and Sankey
•British Spiders - E. F. Staveley (1866 1st Edition)
•Catalogue of American Spiders part one (1939) - Petrunkevitch
•Collected Papers on Spiders of Wladyslaw Kulczynski Vols. I, II and III
•Common Spiders (American) - J. H. Emerton (1902 1st Edition)
•English Spiders -Thomas Martyn. 1793 1st Edition
•Fauna of India – Spiders Vol. I and II 1980/82 – B.K. Tikader
•Groliers Amazing World of Animals - Arthropods 2 copies
•Guide to Spiders of Britain & Northern Europe - Dick Jones
•Harvesting Ants & Trapdoor Spiders - J.T. Moggridge (1873 1st Edition)
•How to begin the Study of Spiders – J. L. Cloudsley-Thompson
•How to Know the Spiders (American) - B. J. Kaston
•How to Know the Spiders (American) - Vance Randolph
•Introduction to Arachnology - T.H. Savory (1974 1st Ed)
•Keeping Spiders in Captivity - F. Murphy
•Keys to the families of British Spiders - L.M. Jones-Walters (1989)
•Life of the Spider - J. Crompton (1955 Paperback)
•New Zealand Spiders - R.R. & L.M. Forster
•New Zealand Spiders; Part 1 R.R. Forster
•New Zealand Spiders; Part 2 R.R. Fortster /C.L. Wilton
•New Zealand Spiders; Part 3 R.R. Forster
•New Zealand Spiders; Part 4 R.R. Forster/C.L. Wilton
•New Zealand Spiders; Part 5 R.R. Forster/A.D. Blest
•New Zealand Spiders; Part 6 R.R. Forster/A.F. Millidge/D.J. Court
•Paleozoic and Mesozoic Arachnida of Europe (1953) - Petrunkevitch
•Pauki (Russian Spiders) - A.V. Ivanov
•Provisional Atlas of British Spiders Vol. I and II – Harvey, Nellist and Telfer
•Records Zoological Survey: Heteropodidae – Sethi/Tikader
•Records Zoological Survey: Spinning apparatus – Ramakrishna/Tikader
•Southern African Spiders - Martin R. Filmer
•Spider - Dick Jones
•Spider Fauna of Malham Tarn - E. Duffey 1963
•Spider Wasps; Identification Guide - M. C. Day
•Spiderwatch – Astri and John Leroy (African Spiders)
•Spiders – A Pocket Companion
•Spiders - Paul Sterry 2 copies
•Spiders - Barbara Taylor
•Spiders (African) - G. Newlands/E. de Meillon
•Spiders - W. S. Bristowe
•Spiders – Michael Chinery
•Spiders - H. S. Fitch
•Spiders - T. H. Savory ( 2 copies)
•Spiders - C. Warburton (1912) ( 2 copies)
•Spiders - Ralph Whitlock
•Spiders Photo guide - P. Hillyard
•Spiders and their Kin - H. W. Levi/L. R. Levi
•Spiders & Allied Orders of the British Isles - Savory (1935 1st Ed)
•Spiders & Allied Orders of the British Isles - Savory (1945 2nd Ed) 2 copies
•Spiders and Beetles - S. N. Sedgewick
•Spiders, Men & Scorpions - T.H. Savory (1961 1st Edition) 2 copies
•Spiders - National Geographic Society (H/bk)
•Spiders, Scorpions, Centipedes & Mites - J.L. Cloudsley -Thompson (1958)
•Spiders in Ecological Webs - D.H. Wise
•Spiders of Britain & Northern Europe - Michael J. Roberts
•Spiders of Connecticut – Kaston
•Spiders of Dorset (Vol. I and II) – Rev. Octavius Pickard-Cambridge (1879)
•Spiders of Gt. Britain & N. Ireland (part 1) - Blackwall (1861) (2 copies
•Spiders of Southern Africa - J. H. Yates
•Spiders of Leicestershire and Rutland - J. Crocker/J. Daws
•Spiders of Leicestershire and Rutland: Millenium Atlas - J. Crocker/J. Daws
•Spiders of the World - R. and K. Preston-Mafham
•Spiders of Leicestershire and Rutland (Millenium Atlas) - J. Crocker/J. Daws
•Spiders of the United States – Headstrom
•Spiderland - R. A. Ellis (1912 1st Edition)
•Spinnen - Bellman
•Spinnen – Hahn
•Records of Zoological Survey of India - Heteropodidae – V. D. Sethi/ B. K. Tikader
•Records of Zoological Survey of India – Role of spinnerets – Ramakrishna/Tikader
•Swedish Araneae, part II – Dictynidae to Salticidae – Sven Almquist
•Tarantulas – Jon Coote
•Tarantula (your first) – Russell Willis
•Tarantula Classification Guide - A. Smith
•The Arachnida of London – T. H. Savory 1957 (Booklet)
•The Book of the Spider - P. Hillyard (H/bk)
•The Book of the Spider - P. Hillyard (P/bk)
•The Black Widow Spider - R.W. Thorp & W.D. Woodson
•The Book of Spiders and Scorpions - R. Preston -Mafham
•The Book of Spiders and Scorpions - R. Preston -Mafham
•The Comity of Spiders - Vols 1 & 2: 1939/41 - W.S. Bristowe
•The Hunting Wasp - J. Crompton (1948 1st Edition, H/bk)
•The Hunting Wasp - J. Crompton (Scientific Book Club Edition)
•The Life of the Spider - J. H. Fabre (2 copies)
•The Puffin Book of Australian Spiders – Helen Hunt
•The Red Hourglass (Lives of the predators) - Gordon Grice
•The Silken Web – B. Brunet
•The Spider - J. Crompton (1950 1st Edition)
•The Spiders of Gt. Britain & Ireland P/B Vol 1 - M. J. Roberts
•The Spiders of Gt. Britain & Ireland P/B Vol 2 - M. J. Roberts
•The Spiders of Gt. Britain & Ireland H/B Vol 1 - M. J. Roberts
•The Spiders of Gt. Britain & Ireland H/B Vol 2 - M. J. Roberts
•The Spiders of Gt. Britain & Ireland H/B Vol 3 - M. J. Roberts
•The Spiny Orb-Weaver – Micrathena and Chaetacis – Herbert W. Levi
•The True Book about Spiders - Savory
•The Tarantula Keepers Guide - Schultz
•The World of Spiders - W. S. Bristowe (1958 1st Edition)
•The World of Spiders - W. S. Bristowe (1971 Reprint)
•Webs in the Wind – Duncan
•What's so special about Spiders Article Nat. Geographic Aug,'71
•The Spider that lives Underwater Article Nat. Geographic May,'72
•All Eyes on Jumping Spiders Article Nat. Geographic Sep,'91
•Portia Spiders Article Nat. Geographic Nov,'96
•Deadly Silk Article Nat. Geographic Aug,’01
No.9 Spider