A Computational Introduction to Number Theory and Algebra
- By Victor Shoup (Cambridge University Press, 2005). Full text free in PDF, list of errata, supplementary exercises.
- http://shoup.net/ntb/

Prime Numbers
- By Richard Crandall and Carl Pomerance. Table of contents, with Primekit, the associated Mathematica software to order on-line.
- http://www.perfsci.com/primenumbers.htm

Algorithmic Number Theory
- Eric Bach and Jeffrey Shallit. Errata, bibliography in BibTeX format.
- http://www.cs.uwaterloo.ca/~shallit/ant.html

The Prime Number Theorem
- By G.J.O. Jameson, Cambridge University Press (2003). Preface, table of contents, chapter introductions; errata.
- http://www.maths.lancs.ac.uk/~jameson/pntdescr/

An Introduction to Number Theory
- By G. Everest and T. Ward. Springer, 2005. Table of contents and introduction in PDF.
- http://www.mth.uea.ac.uk/arithmetic/

Recurrence Sequences
- Graham Everest, Alf van der Poorten, Igor Shparlinski and Thomas Ward (AMS, 2003). AMS Surveys and Monographs, volume 104. Table of contents and introduction (PDF, HTML), reviews.
- http://www.mth.uea.ac.uk/sequences/

Elliptic Curves: Number Theory and Cryptography
- By Larry Washington (Chapman+Hall/CRC, 2003). Contents, errata.
- http://www.math.umd.edu/~lcw/ec.html

Introduction to Cyclotomic Fields
- 2nd ed. by Larry Washington (Springer). Errata.
- http://www.math.umd.edu/~lcw/cyclo.html

Factorizations of b^n+/-1
- b=2,3,5,6,7,10,11,12 Up to High Powers.By John Brillhart, D.H. Lehmer, J.L. Selfridge, Bryant Tuckerman and S.S. Wagstaff, Jr. Third edition, AMS, 2002. Complete text available for free download in PDF.
- http://www.ams.org/online_bks/conm22/

The Third Edition of the Cunningham Book
- Factorizations of bn ± 1, b = 2, 3, 5, 6, 7, 10, 11, 12, up to High Powers, by John Brillhart, D.H. Lehmer, J.L. Selfridge, Bryant Tuckerman, and S.S. Wagstaff, Jr. An electronic book: links to full text [PDF] and tables.
- http://www.cerias.purdue.edu/homes/ssw/cun/third/

Antwerp IV
- Modular Forms of One Variable vol.IV, Bryan Birch and Willem Kuyk edd (Springer) scanned by William Stein.
- http://modular.fas.harvard.edu/Tables/antwerp/

Introduction to the Theory of Numbers
- G.H. Hardy and E.M. Wright. Index to the classic text (4th/5th edition 1979) which was never published by OUP. HTML, DVI, PS.
- http://www.mathpropress.com/HardyAndWright.html

Primes of the Form x^2 + ny^2
- By David A. Cox, Amherst College (Wiley, 1989). Errata.
- http://www.cs.amherst.edu/~dac/primes.html

Taming Wild Extensions
- By Lindsay N. Childs. Introduction.
- http://math.albany.edu:8000/~lc802/mono.html

Analytic Number Theory and Applications
- To Prof. Anatolii Alexeevich Karatsuba on the occasion of his 60th birthday. A collection of papers in DVI and PostScript format.
- http://wain.mi.ras.ru/mian218.htm

Area, Lattice Points, and Exponential Sums
- Martin Huxley (OUP/LMS, 1996). Author's page with summary and errata.
- http://www.cf.ac.uk/maths/people/huxley1.html

eBooks in Number Theory
- Mainly connected with Smarandache problems. PDF, HTML, WORD, WP, TeXT formats.
- http://www.gallup.unm.edu/~smarandache/eBooks-otherformats.htm

Paul Garrett's Crypto and Number Theory Lecture Notes
- Introduction to cryptology, number-theory, and algorithms. Protocols. Symmetric versus asymmetric systems. Stream, block ciphers. One-way functions, signatures. Key management. (Pseudo-) random number generation. Permutation groups. Primes, Euclidean algo
- http://www.math.umn.edu/~garrett/crypto/

Discovering Number Theory
- A textbook by John Jones and Jeff Holt.
- http://math.la.asu.edu/~jj/dnt/

Fundamental Number Theory with Applications
- Richard A. Mollin. Contents.
- http://www.math.ucalgary.ca/~ramollin/fnt2.html

Voronoi's Impact on Modern Science
- Edited by P.Engel and H.Syta. Contents, ordering information.
- http://www.imath.kiev.ua/~syta/vorbook.html

Local Fields and Their Extensions, Second Edition
- I.B. Fesenko, S.V. Vostokov. PostScript.
- http://www.dpmms.cam.ac.uk/Algebraic-Number-Theory/0319/

Collected Papers of Sarvadaman Chowla
- Edited by James G. Huard and Kenneth S. Williams. Contents.
- http://www.canisius.edu/~huard/chowla.html

An Invitation to Arithmetic Geometry
- Dino Lorenzini. Additions, corrections, review, preface.
- http://www.math.uga.edu/~lorenz/book.html

Notes on Fermat's Last Theorem
- Alf van der Poorten (Wiley, 1996). Contents, reviews.
- http://www.maths.mq.edu.au/~alf/NotesonFLT.html

Automorphic Forms and Representations
- Dan Bump. Errata, contents, virtual study group.
- http://math.stanford.edu/~bump/book.html

Gauss and Jacobi Sums
- Bruce C. Berndt, Ronald J. Evans, and Kenneth S. Williams (Wiley, 1998). Contents, errata, remarks, reviews.
- http://math.ucsd.edu/~revans/errata/errata.html

A Friendly Introduction to Number Theory
- J.H. Silverman. Contents, preface, errata, further material.
- http://www.math.brown.edu/~jhs/frint.html

Reciprocity Laws from Euler to Eisenstein
- Franz Lemmermeyer (Springer, 2000). Contents, bibliography, errata.
- http://www.rzuser.uni-heidelberg.de/~hb3/rec.html

Sphere Packing, Lattices and Groups
- J. H. Conway and N. J. A. Sloane (Springer, 1998). Contents, errata (including a missing page), updated tables and database.
- http://www.research.att.com/~njas/doc/splag.html