Whitaker, T D:  A history of the original parish of Whalley and Honour of Clitheroe in the counties of Lancaster and York
(First ed. 1800)
Includes Great Harwood. As was usual for these early histories the readers were mainly from the landed classes and the focus mostly on the descent of these families and ecclesiastical history. It includes pedigrees of local families, but these should be used with caution.
Greatest value is the reproduction, sometimes in Latin, of various ancient documents.
Fourth edition of 1872 available at Internet Archive:

Abram, W A:  A History of Blackburn Town and Parish
Published 1877.
This book is a good, comprehensive history which goes further than the landed gentry in its scope. Short biographies of local families of the yeoman class are included, but again should be treated with some caution.

Victoria History of the County of Lancaster
Published 1911
An early volume in the VCH series it deals mainly with the descent of the manor and the church.
Available online here:

Ainsworth, R: Old Homesteads of Accrington and District
Published 1928.
Originally appearing in the Accrington Observer as a series of articles on the various settlements in the area of Accrington. Whilst examining in detail places in other towns, even places that had ceased to exist, for Great Harwood only Martholme is covered.
This may still be in copyright and there are no volumes online. Libraries will have copies, but may be reference only.

Eaton, H E: Genius of Great Harwood: John Mercer
Great Harwood Civic Society: Owd Arrod
Pollard, L: Great Harwood Gleanings
Pollard, L: Great Harwood Miscellany
Pollard, L and Eaton, H: Old Harwood
Pollard, L.: People and places in Great Harwood
Pollard, L: Story of a Village Church

Louie Pollard and Harry Eaton worked on several volumes of local history during the 1970s and 1980s, jointly and separately. These are still in copyright but should be available in local libraries or sometimes copies do appear on eBay and other sale sites.
Great Harwood Gleanings and The Story of a Village Church are both very good local and social histories.

Rothwell, M. Industrial Heritage of Great Harwood
First published in the 1970s this covers the industrial history of the town. A new edition has recently been published by Hyndburn Local History Society and is available to buy or should be available in local libraries.

Click here for publications by Great Harwood History Society