Twistors- What are they?  
   A set of notes introducing spinors and twistors.
   http://www.compsoc.net/~fedja/twistors/twistors.html

Dimensional Analysis  
   A simple review of the powerful technique of dimensional analysis.
   http://www.physics.uoguelph.ca/tutorials/dimanaly/

Mathematical Methods I  
   This site contains the complete lecture notes and homework sets for PHYCS498MMA, a course of mathematical methods for physics given to entering graduate students, and senior undergraduates, at the University of Illinois at Urbana-Champaign.
   http://w3.physics.uiuc.edu/~m-stone5/mma/mma.html

Hyperreal World  
   Nonstandard analysis and its applications to quantum physics, by H.Yamashita. Mixed English/Japanese.
   http://www.sun-inet.or.jp/~leibniz/math/

Discrete Self-trapping Equation  
   A bibliography in BibTeX format for those interested in discrete nonlinear Schrödinger type equations.
   http://www.ma.hw.ac.uk/~chris/dst/

Elastic Strain Soliton Visualization  
   Windows demonstration program download.
   http://www.csa.ru/Inst/bogd_dep/nonlin/vizual.htm

Celestial Mechanics Research  
   Links, animations, references, and a brief description of research into n-body problems.
   http://www.math.washington.edu/~hampton/research.html

This Week's Finds in Mathematical Physics  
   This is a column written about modern topics in mathematical physics.
   http://math.ucr.edu/home/baez/TWF.html

Holomorphic Methods in Mathematical Physics  
   This set of lecture notes by Brian C. Hall gives an introduction to holomorphic function spaces as used in mathematical physics. The emphasis is on the Segal-Bargmann space and the canonical commutation relations.
   http://arxiv.org/abs/quant-ph/9912054

Lectures on Orientifolds and Duality  
   Notes by Atish Dabholkar on orientifolds emphasizing applications to duality.
   http://arxiv.org/abs/hep-th/9804208

Homological Methods in Mathematical Physics  
   These lecture notes by Joseph Krasil'shchik and Alexander Verbovetsky are a systematic and self-contained exposition of the cohomological theories naturally related to partial differential equations.
   http://arxiv.org/abs/math.DG/9808130

Recent Developments in Skyrme Models  
   An introduction by T. Gisiger and M.B. Paranjape to recent, more mathematical developments in the Skyrme model. The aim is to render these advances accessible to mainstream nuclear and particle physicists.
   http://arxiv.org/abs/hep-th/9812148

An Introduction to Noncommutative Geometry  
   A set of lecture notes by Joseph C. Varilly on noncommutative geometry and its applications in physics.
   http://arxiv.org/abs/physics/9709045

Euclidean Geometric Transforms for Physics  
   A new method of correlating physics formulas to derive one formula from a related formula using Euclidean geometry to represent the inter-relationship of physics formulas.
   http://physicstransforms.tripod.com/

Kinetic Theory and its Applications.  
   This resource is devoted to mathematical aspects of kinetic theory and its applications in physics and chemistry.
   http://kinetic.boom.ru

Open Problems in Mathematics and Physics  
   Links to open problems in mathematics, physics and other subjects.
   http://www.geocities.com/ednitou

Non Commutative Geometry  
   Preprints of Alejandro Rivero about Connes's NCG and the Standard Model. Also some historical articles on related topics.
   http://dftuz.unizar.es/~rivero/research/index.html

Symplectic Geometries in Quantum Physics and Optics  
   A comparison of symplectic geometry with Euclidean or unitary geometries in quantum physics and optics
   http://arxiv.org/abs/quant-ph/9509002

Topology and Physics  
   An essay by C. Nash on the historical connection between topology and physics.
   http://arxiv.org/abs/hep-th/9709135

Period and energy in one degree of freedom systems  
   An article by Jorge Rezende, University of Lisbon (PDF).
   http://gfm.cii.fc.ul.pt/Members/jr_periodenergy1.pdf

Radial Symmetric Fourier Transforms  
   Fourier transforms of radially-symmetric functions can be performed efficiently using the Hankel transform of order zero. Illustrations of the method are presented, and of the Gibbs' phenomenon.
   http://cadcwww.dao.nrc.ca/ADASS/adass_proc/adass3/papers/birkinshawm/birkinshawm.html

Five Lectures on Soliton Equations  
   A self-contained review by Edward Frenkel of a new approach to soliton equations of KdV type.
   http://arxiv.org/abs/q-alg/9712005

Complex Geometry of Nature and General Relativity  
   A paper by Giampiero Esposito attempting to give a self-contained introduction to holomorphic ideas in general relativity. The main topics are complex manifolds, spinor and twistor methods, heaven spaces.
   http://arxiv.org/abs/gr-qc/9911051

Local Quantum Physics Crossroads  
   An international forum for information exchange among scientists working on mathematical, conceptual, and constructive problems in local relativistic quantum physics (LQP).
   http://www.lqp.uni-goettingen.de/lqp/

The Dirac Delta Function  
   A brief introduction to the properties and uses of the Dirac delta function.
   http://www.sci.hkbu.edu.hk/msc/full/billy/node5.html#SECTION00120000000000000000

Clyde Davenport's Commutative Hypercomplex Mathematics  
   Summary and application as it relates to electromagnetic theory and special relativity.
   http://home.usit.net/~cmdaven/cmdaven1.htm

Solitons  
   Resources at Heriot-Watt University. Meetings, local and other links.
   http://www.ma.hw.ac.uk/solitons/

Twistor Web  
   A new approach pioneered by Roger Penrose, starting with conformally-invariant concepts, to the synthesis of quantum theory and relativity. Some papers on-lin.
   http://users.ox.ac.uk/~tweb/

Doing Physics with Quaternions  
   A research effort to see how much of standard physics can be done using only quaternions, a 4-dimensional division algebra.
   http://world.std.com/~sweetser/quaternions/qindex/qindex.html

Geometry and Duality  
   Lecture notes from the ITP miniprogram on Geometry and Duality
   http://online.itp.ucsb.edu/online/geom/

Twistor Theory  
   Description of Twistor Theory
   http://www.rdegraaf.nl/index.asp?sND_ID=436182

Journal on Applied Clifford Algebra  
   Journal devoted to the development of Geometric Analysis in particular through the use of Clifford Algebras, Quaternions, Hypercomplex Analysis and Multivector Techniques. Main emphasis en the applications to Physics.
   http://clifford-algebras.org

Differential Equations and Oscillations  
   Many problems in physics are described by differential equations. As a complete discussion of differential equations is beyond the scope of this chapter we will deal only with linear first and second order ordinary differential equations.
   http://www.physics.orst.edu/~rubin/nacphy/ComPhys/DIFFEQ/mydif2/

Visual Mathematical Physics  
   Collection of animated gif pictures describing the solutions of the main partial differential equations such as Laplace, Poisson, string and membrane oscillations and heat conduction.
   http://www.isir.minsk.by/eng/educ/mathphys/

Klaus Brauer's Soliton Page  
   Presents a history of J.S.Russell's discovery of solitary waves, and animations of one-, two- and three-soliton solutions to the Korteweg-de Vries equation. Includes an article in PDF format on finding exact solutions to the KdV equation using the method
   http://www.usf.uni-osnabrueck.de/~kbrauer/solitons.html

Inexplicable Secrets of Creation  
   Relationships between number theory and physics.
   http://www.maths.ex.ac.uk/~mwatkins/isoc/

Intrinsic Localized Modes  
   Dynamics of defect-free periodic lattices in terms of plane wave phonons. Web text by Albert J. Sievers, Cornell.
   http://www.lassp.cornell.edu/~sievers/ilm/