This delightful book is a story from the 1920s of a great engineer's courtship of an intelligent young woman, half his age, through an exchange of letters about mathematics - the only form of intercourse that her father would allow. Barnes Wallis, inventor of the 'Bouncing Bomb' of Dam Busters fame, fell in love at age 35 with his 17–year old second cousin, Molly Bloxam, who was just about to begin her university science course.

As socially diffident as he was intellectually assured, Barnes took his charge, and opportunity, seriously. His sequence of letters includes most of a course in what today would be A–level Mathematics. His always apologetic concern that Molly should not be bored or perplexed shines through every letter, mirrored by her own reassurances that he makes things clearer than she had thought possible.

The suppressed passion on both sides is as far from current conventions as the language of upper middle–class England of the time. (That 'topping' and 'ripping' should be common adjectives of approbation, and 'jolly' the dominant adverb, should not surprise us in an age where 'bad' means excellent, any more than the lack of any real opportunity for the couple to 'chill' together. )

Mary Stopes–Roe, their daughter, has skilfully edited and linked the letters into a story with many different attractions: the careful depiction of English life in the 1920s; the slowly developing romance between two contrasting but complementary people; the sweet naïveté, to our ears, of their writing; and the quality of the mathematics teaching. It must be a unique courtship and one which deeply unites intellect and feeling.

The teaching begins when Barnes, out of a job because airship design closed down after The Great War, has taken a job as a schoolmaster in Switzerland. He teaches from first principles assuming, as those expert in mathematics so often do, that describing the logical structure of the mathematics provides the best learning sequence.

This works well with students as able as Molly clearly was. Barnes is in complete command of the subject, adding some history of its development and enlivening the tale with anthropomorphic metaphors — "the Duke of Delta Eks is a very wee and obliging sort of fellow who has the peculiar property that he will fade into the background at the merest suggestion on our part that he should become 'indefinitely reduced'." Any student, or teacher, of A–level Mathematics will find this a useful and thought–provoking view of the subject.

Molly's letters of response are models of appreciation and reassurance, cloaked in descriptions of her day–to–day life. They combine filial obedience and propriety with a steadfast resolve to take no real notice of parental disapproval of her unlikely but successful match.

Mathematics With Love is available from Amazon (UK)