
Andrew Loomis wrote some of the best art instruction books ever, however as you may know, they are no longer in print and nearly impossible to find. SaveLoomis.org is a great resource, with html versions of all six of his books. Pdf versions of the books used to be available, but have become very hard to locate. I was fortunate enough to secure pdf versions of all six books and have since put them on my server for others to download and learn from. To my knowledge all of these books, which were published between 1939-'61, are in the public domain and thus are free to distribute.
To download a .rar file containing all six books click here, otherwise click the image of the book you are interested in.