While the digital hunt is tempting, consider purchasing the Dover reprint. It costs roughly the same as a large pizza but provides a lifetime of reference material. If you must use a PDF, check your university library's digital portal first. Spencer’s genius lies in brevity; if you can master his 200 pages, you will have a foundation strong enough to read any modern research paper in biomechanics, geophysics, or advanced fluid dynamics.

Anthony James Merrill Spencer (1929–2008) was a prominent figure in the mechanics community, known for his work on anisotropic materials and fiber-reinforced solids. His "little Longman text" remains one of the most recommended starting points for anyone entering the field of continuum mechanics. Continuum Mechanics A J M Spencer

Before diving into the search for a PDF, one must understand the author. (1929–2008) was a luminary in the field of theoretical mechanics. Educated at Cambridge and a long-standing professor at the University of Nottingham, Spencer’s research focused on finite elasticity, plasticity, and the mechanics of anisotropic materials.