Introduction
This is a listing of sites that legally offer free fiction Mystery, Detective, Thriller and Crime books , for reading and listening (audio).
All of these sites listed have content that is legal for them to distribute and for you to download and/or read online. If you find that any site listed is offering content that can not be legally transferred, please let me know in the comments below.
This list is not comprehensive and if you know of any other sites please post in the comments below or at our forums [2].
A comprehensive alphabetical listing of free books for reading or listening can be found on these pages:
There will be other Mystery, Detective, Thriller and Crime related books at sites listed there, but they are not categorized at the sites.
Libraries are also an excellent source for reading and listening materials. To find out more information on your local library, the links here may help: Library Information [5]
There are 15 other book pages here at Gizmo's covering other various popular book genres and offering links to free online books listed here: Book Genre Pages [6]
Mystery/Detective/Thriller/Crime (fiction)
2020k (Detective) [7] (Mystery/Thriller) [8] Large collection (2,000) available for download in a variety of formats.
Amazon [9] 
has free kindle, mystery and thriller, ebooks for free download after registration. There are 19 free entries in the main listing and clicking on the sub-genres (and sub-sub) will reveal some more. I am not certain if these are available to those outside the USA.
Arthur's Classic Novels (Mystery) [10](Detective 1 [11])(Detective 2) [12] These three links provide a nice collection of classic mystery and detective stories for online viewing.
BlackMaskFiction [13] offers 20 or so free detective stories that were originally published in magazines during 1925 to 1939 for download in pdf.
BookGlutton [14] has interesting collection of 53 free books in its Mystery & Detective section for online reading with the added feature of groups available for discussion of the readings. Nice combination of reading and socializing. Suggested by an anonymous poster. Now requires registration and starting of a book group to read.
BookRix [15] 
has over 60 free detective novels for reading online or download in epub, Sony, Stanza (iPhone) or their BookRix formats. The reading online is in a popup window that reads as an ordinary book. There are some classics that can be found elsewhere, but there are also many unique entries here. The adult oriented books require registration to read or download.
BooksShouldBeFree [16] has a large collection of classic Mystery audio books available for download in very good quality MP3 or as text for reading.
BookYards (Mystery) [17] 109 classic novels available for download in pdf
ClassicLiteratureLibrary [18] offers several detective stories by Dickens and Poe as well as several Sherlock Holmes and Professor Challenger books by Doyle for online viewing.
DailyLit [19] has 33 full free ebooks in its Mystery category and 4 full free ebooks in its Thriller [20] category. These are delivered in installments to your email, hence the "Daily" lit.
eBooksDirectory [21] has a small collection of free mystery novels for download. It is a nice mix of classic and newer novels.
eBooksForAll [22] offers 10 free classic Mystery and Thriller ebooks. these are links offsite, so download and viewing options vary.
eBookTakeaway [23] has a good size collection in their crime/detective/mystery/thriller category for download in pdf, html or ebook text.
FeedBooks (Mystery/Detective) [24](Thriller) [25] has about 165 classic works between these two sections available for download in a variety of formats.
FreeeBooksBlog [26] has links to 4 unique free mystery novels for download in varying formats in their Mystery [27]category as well as one entry in their Crime [28] category.
Free eBooks.net (Mystery) [29] has an interesting collection of 142 mystery novels available for download.
FreeOnlineNovels [30] has about a large collection of links to mystery novels available online.
GetFreeeBooks [31] offers 10 free unique ebooks in its Mystery fiction [32] category as well as 11 free ebooks in its Thriller & Suspense [33] category.
Globusz (Mystery) [34] has 10 books available for online viewing or download.
GoogleBookSearch (Mystery) [35] has 48 classic mystery novels available for online viewing or download as pdf.
Gutenberg (Mystery) [36](Detective) [37](Crime Fiction) [38] between these three sections, Gutenberg has a large collection available for download in several formats.
JimDeFilippi [39] offers 8 of his crime novels for free download in pdf.
KnowledgeRush [40] has about 60 works of several classic mystery writers available for free download in pdf or html in its Mystery category.
ManyBooks (Mystery/Detective) [41] has an interesting collection of 588 books available for download in a variety of formats.
Munsey's (Mystery) [42] has 736 mystery novels available in a variety of formats
MysteryNovelist [43]offers the romance mystery, Snow Angels, by Barbara W. Klaser for free reading online.
obooko [44] offers 30 free books by self publishing authors for download. Free registration is required.
OnlineBooksPage (Mystery/Detective) [45] Small amount of links to mystery and detective novel downloads.
Online Novels.blogspot [46]has links to a large number of mystery/thriller novels available online for viewing and/or download. These are unusual entries not found elsewhere.
Project Gutenberg Australia [47] has a large collection of novels, some available for online viewing and some for download.
PublicBookShelf (Mystery/Suspense) [48] 37 novels available for online viewing
RichardEngling [49] offers his futuristic detective novel, Body Mortgage, for free download. Registration for a newsletter is required.
Robert Burton Robinson offers a number of free books and short stories for free online viewing [50] and for free download in pdf. [51]
[52]
Rob'sNovelsandNovellas [53] has several novellas and novels for online viewing in its Mystery and Thriller section. These are original and unique entries not found elsewhere.
SunDogStories [54]offers the adult oriented crime story, Lucky's Dream, for free online viewing.
TopMystery [55] A good amount of each of the limited authors listed are available for online viewing or download
Mystery/Detective/Thriller/Crime (fiction) (audio)
AudioBooks has Agatha Christie's Miles of Mystery and The Wisdom of Father Brown by G.K.Chesterton along with 5 chapters of Black Jack Justice under Detective [56]. There are also several chapters of the Red Panda Adventure along with Mark Twain's The Stolen White Elephant under Mystery [57]. You must register (free) to download.
AudioBooksForFree has a large number of works in this genre. There are 250 free audio books under Crime Mystery [58]; 209 free audio books under Thriller [59](although most also involve supernatural); 19 free audio works under Spy Stories [60] and 16 free audio books under Terrorists [61]. Downloads in MP3. The free downloads are in low quality (8kbps) and registration is required.
AudioBookTreasury [62] has The Adventures of Sherlock Holmes (11 works) available for free download in MP3 (or complete work in Zip) or for listening online.
BooksShouldBeFree [16] has 34 classic Mystery audio books available for download in very good quality MP3 or as text for reading.
LibriVox has 147 free audio books under their Mystery [63]genre as well as 11 works under their Spy Stories [64] genre. These are available for download in MP3 (64kb/128kb) or ogg vorbis. All are human read.
MariaLectrix [65] has a good number of works in their Mystery category, but they are separated and often the parts are posted in different blog entries making it a bit difficult to get the whole audio book. Some link to other sites for download, others are for listening online there.
PodioBooks has 12 unique entries under Mystery [66] and 9 unique works under Thrillers [67] available for download in very good quality MP3. These were originally released as podcasts (and still are) but most are completed.
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