Classic/Free books about Astronomy, Physics, Mathematics:
Astronomy:
Ptolemy, Copernicus and Kepler books
Kesten "Copernicus And His World"
Kepler "Harmonies of the world"
Loomis "A Treatise on Astronomy"
Pannekoek "History of Astronomy"
Berry "A short history of astronomy"
Wilson "Astronomy Through the Ages"
Baker and Fredrick "Astronomy"
Dreyer "A History Of Astronomy From Thales To Kepler"
Flammarion and Gore "Popular Astronomy"
Hiltner "Astronomical Techniques"
Hoyle "Frontiers of astronomy"
Jauncy "Radio Astronomy And Cosmology"
Newcomb "Astronomy for everybody"
Pankaj Jain "Introduction to Astronomy and Astrophysics"
Voroncov-Velyaminiv "Astronomy" ( djvu, russian)
Mathematics:
Euclid "Elements. Barrow Translation" djvu
Apollonius of Perga "Treatise of Conic Sections"
The Geometrical lectures of Isaac Barrow
L'Hospital "The method of Fluxions"
L'Hospital "The method of Fluxions russian" djvu
Newton "Universal Arithmetics"
Euler "Introduction to Analysis of the Infinite vol.1 latin"
Euler "Introduction to Analysis of the Infinite vol.2 latin"
Euler "Introduction to Analysis of the Infinite vol.1 russian"
Euler "Introduction to Analysis of the Infinite vol.2 russian" djvu
Goursat "A Course in Mathematical Analyses vol. 1"
Goursat "A Course in Mathematical Analyses vol.2 part1"
Goursat "A Course in Mathematical Analyses vol.2 part2"
Witteker, Watson "A Course Of Modern Analysis"
Lagrange "Lectures On Elementary Mathematics"
Hadamard "The psychology of invention in Mathematics"
Gardner "Recreational_Mathematics"
Gardner "Mathematical Puzzles and Diversions"
Gardner "Fads-and-Fallacies-in-the-Name-of-Science"
Gardner "Entertaining Mathematical Puzzles"
Gardner "A Celebration of His (12 + 3 - 4 + 5 + 67 + 8 + 9)th Year"
Gardner "The colossal book of mathematics"
Polya "The Stanford Mathematics Problem Book"
Polya "Problems-and-Theorems-in-Analysis-I"
Polya "Heuristic_reasoning_in_number_theory"
Polya "Induction_And_Analogy_In_Mathematics"
Polya "Mathematics and Plausible Reasoning"
Polya "Patterns_Of_Plausible_Inference"
Buchele "The Story of Flatland"
History of Mathematics:
Acheson "Calculus Story. Mathematical Adventure"
Boyer "A History Of Mathematics"
Burton "History of Mathematics"
Cajori "A HISTORY OF MATHEMATICS"
Cajori "A History of Mathematical Notations"
cajori "Teaching and history Of Mathematics In US"
Chemla "The history of mathematical proof in ancient traditions"
Cooke "The History of Mathematics"
Finashin "A History Of Math Concepts"
Hodgkin "A History of Mathematics From Mesopotamia to Modernity"
Kline "Mathematical Thought From Ancient To Modern Times"
Newman "The World Of Mathematics Volume 1"
Rosenthal "The History of Calculus"
Sarton "The-Study-Of-The-History-Of-Mathematics"
Smith "History Of Mathematics Vol 1"
Smith "History Of Mathematics Vol 2"
Smorynski "History of mathematics"
Stillwell "Mathematics and Its History"
Struik "A Concise History Of Mathematics"
Allman " Greek Geometry from Thales to Euclid"
Boyer Merzbach " History of Mathematics"
Heath " A History of Greek Mathematics Vol.1"
Heath " A History of Greek Mathematics Vol.2"
Mechanics:
Lagrange "Analytical Mechanics"
Laplace "A Treatise of Celestial Mechanics"
Tisserand "Traite de Mecanique Celeste, Tome III"
Poincare "New Methods of Celestial Mechanics. Volumes I and II" djvu
Poincare "New Methods of Celestial Mechanics. Volume III"
Fitzpatrick "An Introduction To Celestial Mechanics"
Collins "Foundations Of Celestial Mechanics"
Curtis "Orbital Mech For Engineering Students"
Laplace "Elementary Illustrations of the Celestial Mechanics"
Moulton "An Introduction To Celestial Mechanics"
Subbotin "A Course in Celestial Mechanics Part 2"
Szebehely "Adventures in Celestial Mechanics"
Vinti, Der, Bonavito "Orbital And Celestial Mechanics"
Wintner "The Analytical Foundations of Celestial Mechanics"
Physics:
Bernoulli "Hydrodynamics. Hydraulics"
Maxwell "Treatise on Electrisity and Magnetism"
Heviside "Electromagnetic Theory Vol.1"
Heviside "Electromagnetic Theory Vol.2"
Heviside "Electromagnetic Theory Vol.3"
Whittaker "A history of the theories of aether and electricity"
Andrade "Structure of the atom"
Born "Einsteins Theory of relativity"
Born "Physics in my generation"
Born "The Born-Einstein Letters"
Zommerfeld "Atomic Structure And Spectral Lines"
Zommerfeld " Partial Differential Equations in Physics"
Zommerfeld " Lectures On Theoretical Physics 1 - Mechanics"
Zommerfeld " Lectures On Theoretical Physics 4 - Optics "
Planck "Introduction to Theoretical Physics vol. 1"
Planck "Introduction to Theoretical Physics vol. 4"
Planck "Introduction to Theoretical Physics vol. 5"
Planck " Eight Lectures on Theoretical Physics"
Planck "Origin and Development of the Quantum Theory"
Planck "The universe in the light of modern physics"
Planck "Theory Of Heat Radiation"
Planck "Treatise on Thermodynamics"
Planck "Where Is Science Going"
Eddington " Science and the Unseen World"
Eddington " Space, Time and Gravitation"
Eddington " Stellar Movements and the Structure of Universe"
Eddington " The Expanding Universe"
Eddington " The Mathematical Theory of Relativity"
Eddington " The Nature of Physical World"
Eddington " The Philosophy of Physical Science"
Eddington " The Theory of Relativity"
" Sir Arthur Eddington and the Foundations of Modern Physics"
De Broglie " An Introduction to the Study of Wave Mechanics "
De Broglie " Matter and Light "
Dirac " General Theory of Relativity "
Dirac " The Principles of Quantum Mechanics " "
Thomson "Treatise on Natural Phylosophy "
Thomson " Popular Lectures and Addresses vol I "
Thomson " Mathematical and Physical Papers "
Russel " Lord Kelvin his Life and Work "
Thompson " The Life of William Thomson "
Biology:
Caroluis Linnaeus " The Animal Kingdom"
Caroluis Linnaeus " Three Grand Systems: Animals, Vegitables, Mineralis"
Jackson " Caroluis Linnaeus life "
Gilbert " Developmental Biology "
Lamarck " Zoological Philosophy "
Nordenskiold " The History of Biology "
Science History:
Koerner " Linnaeus: Nature and Nation "
Murray " Science and Scientists in the XIX century "
Singer " Greek Biology and Greek medicine "
Singer " Short History of science to the XIX Century"