Jochnowitz, Naomi  
   University of Rochester. Algebraic number theory, modular forms, p-adic modular forms.
   http://www.math.rochester.edu/people/faculty/what/

Jiménez, Enrique González  
   University of Nottingham. Modular hyperelliptic curves, Q-curves, modular Abelian varieties. Tables of modular curves.
   http://www.maths.nottingham.ac.uk/personal/pmzeg1/

Jacobson, Michael  
   University of Manitoba. Computational aspects of quadratic orders. Papers and thesis.
   http://www.cs.umanitoba.ca/~jacobs/

Jiang, Dihua  
   University of Minnesota. Automorphic Forms, Representation Theory, Number Theory.
   http://www.math.umn.edu/~dhjiang/

Juricevic, Robert  
   University of Waterloo. Analytic number theory. Publications.
   http://www3.sympatico.ca/robert.juricevic/

Jutila, Matti  
   University of Turku. Analytic number theory. Publications.
   http://www.math.utu.fi/staff/jutila.php

Jones, John  
   Arizona State University. Algebraic number theory: Iwasawa theory, the arithmetic of elliptic curves, Galois theory; questions in computational number theory. Tables of number fields of small degree. "Discovering number theory" course materia
   http://math.la.asu.edu/~jj/

Jarden, Moshe  
   University of Tel Aviv, Israel. Field arithmetic. Contains articles, notes, and course information in postscript format.
   http://www.math.tau.ac.il/~jarden/

Jackson, Terence  
   University of York. Geometry of numbers, distribution of values of forms.
   http://www-users.york.ac.uk/~thj1/

Janusz, Gerald J.  
   University of Illinois at Urbana-Champaign. epresentation theory of finite groups, algebraic number theory, Brauer groups, ring theory, algebraic coding theory. Selected publications, teaching material.
   http://www.math.uiuc.edu/~janusz/

Járási István  
   University of Debrecen, Department of Algebra and Number Theory. Publications, thesis.
   http://www.math.klte.hu/~ijarasi/indexen.html

Jarvis, Frazer  
   University of Sheffield. Algebraic number theory and algebraic geometry; in particular, the theory of modular forms and Galois representations. Publications, teaching materials.
   http://www.sheffield.ac.uk/~pm1afj/

Jacobson, Eliot  
   Unicersity of California, Santa Barbara. Algebraic, Elementary and Computational Number Theory. Teaching information, resources.
   http://www.cs.ucsb.edu/~teliot/

James, Kevin  
   Clemson University. Fourier coefficients of modular forms and arithmetic applications. Publications, resources.
   http://www.math.clemson.edu/~kevja/

Jia, Xingde  
   Texas State University - San Marcos. Combinatorial number theory: the problem of thin bases for finite groups, Sidon sequences. Publications, teaching information.
   http://erdos.math.swt.edu/

Joyce, Adam  
   Imperial College, London. Modular forms, Manin constant. Preprints.
   http://www.ma.ic.ac.uk/~ajj198/

Jiménez Calvo, Ismael  
   C.S.I.C., Madrid. Computational number theory. Papers, tables on Hall's conjecture.
   http://www.terra.es/personal9/ismaeljc/home_eng.htm