Maths for Non-Mathematicians
Books that will teach you a little or a lot of interesting things about maths without assuming you remember all your trigonometry.
Flatland: A Romance of Many Dimensions (Dover Thrift)Conceptual Mathematics: A First Introduction to CategoriesA Tour of the Calculus
Flatland: A Romance of Many Dimensions (Dov...
by Edwin Abbott
£2.00
A great, fun book for building up intuitions about higher-dimensional spaces. Buy it for all the 10-year-olds you know.
Conceptual Mathematics: A First Introductio...
by F. William Lawvere

A nice book about the ideas behind abstract maths. The authors tested it on schoolkids and bits of their dialogue are included.
A Tour of the Calculus
by David Berlinski

A purple paean to calculus; its history, the main ideas and why it's all splendid. In places, very wryly amusing.