  This special feature, dedicated to Michael J. Duff FRS on the occasion of his
70th birthday, concerns topics in 'Quantum gravity, branes and M-theory'. These
three intertwining subjects have been central to Duff's work; indeed many of
his contributions have come to define significant aspects of what we actually
mean by these terms. From the discovery of Weyl anomalies to recognising
superstrings in 10 dimensions as a special case of membranes in an
11-dimensional M-theory, Duff's insights have shaped major developments across
these themes. So it is an apposite setting for such a celebration and we are
delighted to be able to include in this collection contributions from many of
the pioneers of quantum gravity, branes and M-theory. The breadth of these
topics has placed little constraint on the multiplicity of ideas appearing in
these pages, from astrophysical black holes to chaotic condensed matter. Again,
this is fitting as Duff's scientific remit spans a remarkable diversity of
motifs, from the fundamentals of M-theory to entanglement in quantum
information.
