This book has informed much of my work as a SEN Coordinator / Head of Learning Support. It provides simple ways to plan interventions, write individual education plans etc. plus it has a range of strategy banks covering Dyslexia, ADHD, Autism, Speech and Language Difficulties and so on.
The role of SENCo can become drowned in paperwork, with the postholder finding themselves reduced to little more than a beaurocrat / administrator - this book helps free you from this burden and allows you to get on with the real work of working with students and colleagues to make schools more inclusive and supportive in practice.
If you're a teacher taking on responsibility in the field of Special Needs / Additional Needs and only have £20 to spend then I would say this is THE one book to buy (for now!).