I did find a site to (sorta) recommend:
http://onlinebooks.library.upenn.edu
Search engine gives you more than you wanted, but it has a few
gems. LOADS of classics. A few useful tech books.
Most everything is in PDF. Many books link to other sites including
Google, Tea Tree Press, archive.org etc.
A few links are not reachable.
I have tracked a few sites for free e-books.
I often find pages tht say "Twenty great places for free ebooks."
Sadly, the writer fails to check any further than the front page
to see if the ebook sites are indeed what they say.
Here are a few DISAPPOINTING sites, that were lucky enough
to be mentioned by a few lazy web-writers. Just a warning,
should you stumble across the same recommendations.
http://4ebooks.org/
"Free programming and computer books" according to the home page.
Very few books found. NONE are free. Cheapest is $0.99 and like nearly everything else on the site, is available from Amazon. The archives are empty. The main pages have ads fro Glade plug-in, baby supplies, and curiously worded ads for software.
memoware.com
"Free Ebooks for Amazon Kindle and Nook" according to the home page.
Unless users can read files in PalmReader, Plucker, iSilo3 and TomeRaider, this
website isn't helpful.
The search engine allows for only Palm OS, EPOC, and Pocket PC.
It also alows for several Document formats, like "Repligo."
Epub and Kindle are NOT on the list.
Under History a few titles are:
Barack Obama's Inaugural Address
The United States Constitution.txt
Castro-Reden 2008 by Fidel Castro
2 Page Ebook by Felix Constantinescu
Romanian translation of the Native American Walum Olum text from the English version.
zillr.org/
An abandoned site with book links.
Each link leads to a search engine with more links.
Each link on the search engine leads to more links.
(Reminds me of the websites that promised "Free Screensavers."
globusz.com
links to other sites. In the form of ads.
Also links to "Free eBooks. Download Now"
which is among others that leads to...
http://www.scribd.com/
Some links say: "Unlimited eBooks On Any Device. 300K+ Titles. Join Scribd Now."
Site says: "Unlimited Books for $8.99 a month."
Manybooks.net
They have a search tool. Typed in "excel."
Best match was, "The Crusade of the Excelsior"
Under computer books such titles as:
The Cyberpunk Fakebook Chapters 1-3, by St. Jude and R.U. Sirius
Man and Superman, A Comedy and a Philosophy, George Bernard Shaw
Not worth browsing.
http://www.snipfiles.com/
Site has screensavers along with ebook. This is suspecious.
Many sites have malware disguised as screensavers.
Found a few good book titles. Oddly they did not list the formats.
Tried to download "Thinking in C."
A web pages opened up. My virus checker prevented it. More bad
news, the further I checked. Aviod this site.
bookyard.com
Typical Computer book title, "Practical Thery Of Programming"
Typed in excel in the search. Among other entries was:
"Using a Excellent Mattress"
Everything is in PDF. An odd assortment of articles disguised as books
under dubious catagories.
freebookspot.es
Always cautious of a site that uses a foreign domain.
I always do a whois search when I notice I am about to use
a foreign domain.
Odd. NO ownership information. Only the second time I
have ever found one of those. The other was a free video
site that was blocked by my virus checker.
Just to be fair, I look for a book on spreadsheets. It had a
few. Clicked and found a few ads for games (NSFW).
Also found several download icons. Usual tip-off for tricks
to get you to click on the wrong one and see either ads or
have downloads for malware.
Found the right one for the book. It is an .rar file.
(OFTEN used to hide malware, but not always.) Clicked
on it and got a page with more ads. Some blocked by my
virus protection. I will skip this site. You have been warned.
onlineprogrammingbooks.com
They are not all free. Each book leads to another site.
Some are actually a series of web pages to read.