How many legs does a harvestman have? When does part of a forward-rolling wheel travel backwards? When is something neither true nor false?

Paul Williams' personal collection of interesting facts, puzzles and conundrums will fascinate all ages. It is divided into five sections according to the reader's likely ease or familiarity with the concepts and processes involved—from Easy through Moderate and Tricky to Difficult and Fiendish. Some brainteasers involve maths, while some relate to language; others are simply curiosities. Children will enjoy the Easy section, while the Fiendish section presents a challenge to the reader's knowledge of mathematics and philosophy.

Paul Williams was born in Bristol and was educated in Swansea and Sussex before attending Clifton College in Bristol. Accepted into Balliol College, Oxford, he attained an MA in Maths, Psychology and Philosophy.

Paul's career has focused on people with learning difficulties. His began as a nursing assistant, then served as a research officer at London and Southampton universities. He then moved into training of planners and staff of community services for people with learning difficulties. Paul lectured in social work at the University of Reading from 1991 to 2007, when he retired. He continues to advocate on behalf of vulnerable people. He is author or co-author of books on self-advocacy by people with learning difficulties, on social work with those people, and on anti-oppressive practice in health and social care. As well as maths and puzzles, Paul's interests include music, poetry and art. His oil paintings have been exhibited locally. Paul currently lives in Trowbridge, Wiltshire.