He was excluded from society and from the editorial staff. They already knew he was talented. Everyone knew that. But they thought he was a troublemaker in editorial meetings. Which wasn't entirely wrong, I must admit: he never kept silent. But this exclusion affected him deeply.

"I was very interested in science, ... but at 12, I didn't yet know whether I would become a physicist or a chemist." There was no pivotal moment. Suddenly, at 13, his interest in mathematics emerged, initially in the form of ordinary geometry. "It was love at first sight. ... I was mathematically gifted, but not a child prodigy."

I never asked why I didn't have grandparents. At my school, all the children were of emigrants, children of foreigners who also had no grandparents at home. And I had very little contact with Germans, had no hobbies, wasn't in any sports club. However, we also had precious little to do with the Jewish community.

Where algebraic K-theory deals with modules, L- theory considers modules with quadratic forms. The L-groups are of interest to topologists because they are the surgery obstruction groups, as described by Wall. Although isomorphism groups of quadratic forms have been studied before, by Witt and others, the topological applications require new algebraic methods.

I wish to thank ... Professor J F Adams, for suggesting that I take up this topic, Andrew Casson, for constant advice and encouragement, and especially for the neat formulation of Theorem 3.1, Dusa MacDuff, for much help in translation from the Russian, the University of Cambridge, for its generous financial support. This work is dedicated to the memory of J T Knight.

I actually met both Daniel Quillen and Dennis Sullivan at the same time, when I spent a year at IHES 1973-4. Sullivan's interest in surgery theory was naturally greater than Quillen's. Both Dan and Jean [Quillen's wife] were kind to me, and I was a frequent visitor at Pavillon 8 of the Residence de l'Ormaille. Although I did not talk to Dan all that much about mathematics there were plenty of other topics, and I was always impressed by his seriousness of purpose and independence of mind, allied with a winning personal modesty.

[Andrew Ranicki] ... came back and sat next to me. I was embarrassed, since Hassler was talking and Andrew was talking and I couldn't concentrate. I tried to ignore him. Then he took out of his pocket what looked like a deck of cards but were tickets to various performances around the Princeton area. He spread them out and asked if I would like to take one of the tickets. I saw a ticket for a play entitled "The Torch Bearers" the next week at the McCarter Theater, which was on campus. I took the ticket, which had the wanted effect of causing Andrew to leave ... I showed up at the theater and found myself seated next to Andrew. We enjoyed the play and I went back to his flat afterwards.

Ida and I were married on 28 October 1979 in the Professors' Lounge of Fine Hall, the Mathematics Department of Princeton University. We were the first two Princeton professors to marry each other. ... Our daughter Carla Helen Emily Ranicki was born in Trenton, NJ on 26 December, 1979.

Andrew Ranicki, Reader in the Department of Mathematics & Statistics, has been appointed to the Chair of Algebraic Surgery. ... He has held visiting positions at the Institut des Hautes Études Scientifiques in Bures-sur-Yvette, the Institute for Advanced Study in Princeton, the University of Kentucky and the University of Göttingen. He was awarded the Cambridge University Smith's Prize (1972), the Junior Whitehead Prize (1983) and the Senior Berwick Prize (1994) of the London Mathematical Society, and was elected a Fellow of the Royal Society of Edinburgh in 1992. Algebraic surgery is a classification method in topology that involves cutting up the high-dimensional geometric objects called manifolds. Fortunately there is no connection with medical surgery, since it is the obstructions to surgery that are of particular interest in the mathematical context.

... this is a carefully written and lucid (but lengthy) account of an important topic in topology which the reviewer strongly recommends to anyone interested in the structure of manifolds.

The book is very nicely written, with numerous applications to topology. It fills a gap in the existing literature on the subject.

The topology of high-dimensional manifolds is a subject of substantial complexity and depth which, compared to other parts of mathematics of comparable importance, suffers from a dearth of monographs. The book under review is therefore a welcome addition to the literature.

In the introduction the author says: "The book actually has two aims: (i) to serve as an introduction to high-dimensional knot theory, using surgery theory to provide a systematic exposition, (ii) to serve as an introduction to algebraic surgery theory, using high-dimensional knots as the geometric motivation." The first aim has surely been achieved successfully, but the reviewer is not sure about the second aim since the book seems to be too huge for this purpose.

Surgery theory, loosely speaking, refers to a variety of algebraic and geometric techniques used to classify manifolds, typically of dimensions 4 or greater. ... Ranicki's book is a readable introduction to this powerful theory that will be useful to a student or beginning user. One thing that such a reader should know, however, is that many of the proofs of the background results are sketched rather than being given in detail.

Written by leading experts in the field, this monograph provides homotopy theoretic foundations for surgery theory on higher-dimensional manifolds. Presenting classical ideas in a modern framework, the authors carefully highlight how their results relate to (and generalise) existing results in the literature. The central result of the book expresses algebraic surgery theory in terms of the geometric Hopf invariant, a construction in stable homotopy theory which captures the double points of immersions. Many illustrative examples and applications of the abstract results are included in the book, making it of wide interest to topologists. Serving as a valuable reference, this work is aimed at graduate students and researchers interested in understanding how the algebraic and geometric topology fit together in the surgery theory of manifolds. It is the only book providing such a wide-ranging historical approach to the Hopf invariant, double points and surgery theory, with many results old and new.

Andrew was an irrepressible spirit in the School of Mathematics who inspired regular visits to Scotland from the very best topologists, often under the banner of Scottish Topology which he helped to run since its foundation in 1981. In addition, he arranged many prestigious seminars, colloquia and events all across the discipline, featuring great mathematicians from throughout the world, including in the last few years Fields Medallists Sir Michael Atiyah, Gerd Faltings, Timothy Gowers and Ed Witten. His house was Edinburgh's mathematical living room, filled with laughter, gossip, and research highlights. In departmental life, he taught a variety of courses mostly in algebra, geometry, number theory and topology, nearly always exposing the students to quadratic forms and giving them glimpses of the rich mathematical world he inhabited. He was a constant advocate for the use of technology in the School, from email through the internet and onto social media, best illustrated by his monumental and multifarious webpage which is now a permanent resource for mathematicians all over the world.

How was Andrew as an advisor? Andrew was kind-hearted, generous, understanding and above all, he was enthusiastic. His enthusiasm for topology and in particular for surgery theory was a powerful beacon for anyone working in the area and especially for his students. He was able to communicate this enthusiasm and impress onto us his elegant understanding of mathematics. ... His sense of humour and hearty laugh combined with a breadth and depth of knowledge not just in mathematics, but also in other areas like music or literature, was always a source of motivation. ... [Andrew put] so much effort in putting together interesting projects for his students, so many hours spent guiding us towards our goals and listening to our attempts … he did all this in his selfless, generous manner ...

Andrew's generosity of spirit, combined with his wife Ida's amazing ability to conjure up magnificent vegetarian meals and imaginative aperitifs, created convivial gatherings of laughter and great good cheer. These often took place in their surprisingly sunny garden, a whole world created by Ida of green beauty, mysterious dense undergrowth and bright blooms, with inviting little spaces to sit and chat. Their house was also a marvellously welcoming space for many mathematicians at all levels, eager students and established prize-winners, their friends and families included.

We go there every year with several friends, a tiny place in the northwest. The landscape is beautiful, and it's the same every year, so I don't have to adjust. My only requirement: an internet connection. It keeps me connected to colleagues all over the world. There are only a few people I can talk to about my work. Without this technology, I would probably be very lonely.

He had been suffering from leukaemia for some time. On 20 February 2018, during a final phone call in the early evening, he told me that the blood values ​​​​symptomatic for this had deteriorated significantly in the past few days and that he would need to be hospitalised for a week. He added: "I'm glad my parents won't know anything about this." News of his death came today from his daughter Carla Ranicki. She wrote: "My mother was with him when he died and said it was very peaceful."