This paper is devoted to recent progress made towards the understanding of closed bosonic
and fermionic string perturbation theory, formulated in a Lorentz-covariant way on Euclidean …

We review recent developments in the construction of heterotic and type II string field
theories and their various applications. These include systematic procedures for determining …

Abstract Foreword; Preface; Notation; 10. Type I and type II superstrings; 11. The heterotic
string; 12. Superstring interactions; 13. D-branes; 14. Strings at strong coupling; 15 …

It is pointed out that string-loop modifications of the low-energy matter couplings of the
dilation may provide a mechanism for fixing the vacuum expectation value of a massless …

A low-energy analysis of macroscopic superstrings is presented and various analogies
between these superstrings and solitons in supersymmetric theories are discussed. These …

It is argued that the superstring tension is not renormalized in perturbation theory for vacua
which preserve N= 1 spacetime supersymmetry. Some implications of this result for …

Perturbative superstring theory is revisited, with the goal of giving a simpler and more direct
demonstration that multi-loop amplitudes are gauge-invariant (apart from known anomalies) …

A ten-dimensional super-Poincaré covariant formalism for the superstring was recently
developed which involves a BRST operator constructed from superspace matter variables …

An unambiguous and slice-independent formula for the two-loop superstring measure on
moduli space for even spin structure is constructed from first principles. The construction …

The N-point amplitudes for the type II and heterotic superstrings at two-loop order and for N⩽
4 massless NS bosons are evaluated explicitly from first principles, using the method of …