Library
From London Hackspace Wiki
Machining
Guerrilla guide to CNC machining and resin casting:
http://lcamtuf.coredump.cx/guerrilla_cnc1.shtml http://lcamtuf.coredump.cx/guerrilla_cnc2.shtml
Electronics
The Giant Internet IC Masturbator: (IC pinouts without pages of ads)
http://www.kingswood-consulting.co.uk/giicm/
Natural/Spoken Language
Step By Step in Esperanto For those who like their languages easy and constructed.