The Samsung Galaxy A series (meaning Alpha) is a line of upper mid-range Android smartphones produced by Samsung Electronics. It is similar to the Samsung Galaxy S series, but with lower specifications and features. The first model in the series, the 4.7-inch Samsung Galaxy Alpha, was first introduced on 13 August 2014.
In December 2014, 3 months after the release of the Galaxy Alpha, Samsung planned to end production of the Alpha in favor of its successor, the similarly-designed, but more competitively-priced Galaxy A series. Samsung's new design philosophy would be fully realized by its 2015 flagship, the Galaxy S6, which combined a unibody metal frame with a glass backing. Since then there have been several models released, most recently the Galaxy A (2016) series, which are similar to the Galaxy S6, and the Galaxy Note 5 flagships, due to its metal and glass buildup, as well as NFC which supports Samsung Pay, Samsung's Adaptive Fast charging feature and increased battery capacity.
In March 2015, Samsung also introduced the Galaxy Tab A series with 8.0 inch and 9.7 inch displays, a S Pen stylus, as well as preloaded Microsoft applications. The S Pen feature on the Galaxy Tab A series, makes the first Samsung Galaxy device to be equipped with the Samsung stylus outside of the Note series. In September 2015, the Samsung Galaxy Tab S2 8.0 and 9.7 series were released, featuring a premium chamfered metal design similar to the first generation Galaxy A series phones.
On January 2, 2017, Samsung unveiled the 2017 edition of the Galaxy A series. Newly improved features include 16-megapixel front and back cameras, a Full HD Super AMOLED display, an Exynos 7 Octa 7880 SoC, a 3D glass display (similar to Samsung Galaxy S6 edge+, Galaxy Note 5 and Galaxy S7), barometer and gyroscope sensors and IP68 certification for water and dust resistance. The new design of the series are very similar to the Galaxy S7 and the S7 Edge, which were released in March 2016. 
The Samsung Galaxy Alpha was introduced on 13 August 2014 and released in September 2014. A high-end device, the Galaxy Alpha is Samsung's first smartphone to incorporate a metallic frame, although the remainder of its physical appearance still resembles previous models such as the Galaxy S5. It also incorporates the Qualcomm Snapdragon 801 or Samsung's new Exynos 5430 system-on-chip, which is the first mobile system-on-chip to use a 20 nanometer manufacturing process. However, the Galaxy Alpha received mixed reviews: although praised for its higher quality build and design in comparison to earlier products, the device was criticized for its modest specifications in comparison to its flagship counterpart, the Galaxy S5, and for being priced too high for what they considered to be a "mid-range" smartphone.
Following its launch, Samsung Electronics CEO JK Shin explained that the Alpha was "built and designed based on the specific desires of the consumer market." The company touted that the Galaxy Alpha would mark a "new design approach" for Samsung's products, and that elements from the Alpha could appear on future Samsung models.
Its operating system is based on Android 4.4.4 "KitKat" with its own version of TouchWiz UI. Several updates were made throughout the world and in April 2015, Android 5.0.2 "Lollipop" was made available through an OTA update.
Release Dates: October 31, 2014 (A3/A5), February 2015 (A7), July 15, 2015 (A8)
The Samsung Galaxy A3 (2015) was announced on October 2014 and released on December 2014. It is considered as a successor to the Samsung Galaxy Alpha.
Its specifications include a 4.5 inch qHD display, a 8MP back and a 5MP front camera, an 64-bit octa-core Qualcomm Snapdragon 410 chipset, 1 or 1.5GB of RAM and a 1900mAh battery. It comes shipped with Android 4.4.4 "KitKat". An update to Android 5.0.2 "Lollipop" started rolling out in May 2015.
The Samsung Galaxy A5 (2015) was announced on October 2014 and released on December 2014. It is considered as a successor to the Samsung Galaxy Alpha.
Its specifications include a 5.0 inch HD display, a 13 MP back and a 5MP front camera, an 64-bit octa-core Qualcomm Snapdragon 410 chipset, 2GB of RAM and a 2300mAh battery. It comes shipped with Android 4.4.4 "KitKat". An update to Android 5.0.2 "Lollipop" started rolling out in May 2015, and later Android 6.0.1 Marshmallow in August 2016. 
Its specifications include a 5.5 inch Full HD display, a 13 MP back and a 5MP front camera, an 64-bit octa-core Exynos 5430 (LTE single-sim model) or Qualcomm Snapdragon 615 (3G/LTE dual-sim model) chipset, 2GB of RAM and a 2600mAh battery. It comes shipped with Android 4.4.4 "KitKat". An update to Android 5.0.2 "Lollipop" started rolling out in May 2015.
The Samsung Galaxy A8 was introduced on July 15, 2015 at an event in China.
The Galaxy A8 is thinner than earlier models from the A-series and Samsung's overall smartphone lineup, measuring 5.9 millimetres (0.23 in) in thickness. Other specifications include a 5.7 inch Full HD display, a 16MP back and a 5MP front camera, an 64-bit octa-core Exynos 5430/5433 or a Snapdragon 615 chipset, 2GB of RAM and a 3050mAh battery. It comes shipped with Android 5.1.1 "Lollipop".
Following its release, the Galaxy A8 is only available in Middle Eastern, Asian and African markets.
Release Dates: December 2, 2015 (A3/A5/A7/A9), March 30, 2016 (A9 Pro), September 30, 2016 (A8)
Samsung Galaxy A9 was introduced on December 2, 2015.
Since January 2016, the Galaxy A9 is only available in China and Hong Kong. The Galaxy A9 provides with a 64-bit Qualcomm Snapdragon 652 octa-core processor, 3GB RAM, 32GB internal memory, a 4000mAh battery with Samsung Adaptive Fast charging feature and a 6-inch Full HD display with Gorilla Glass 4 covering on the back and front sides. It runs on Android 5.1.1 "Lollipop".
Samsung Galaxy A9 Pro was introduced on March 30, 2016. It is very similar to the original Galaxy A9, but with upgraded specifications. Its specifications include a 64-bit Qualcomm Snapdragon 652 octa-core processor, 4GB RAM, 32GB internal memory, a 5000mAh battery with Samsung Adaptive Fast charging feature and a 6-inch Full HD display with Gorilla Glass 4 covering on the back and front sides. It runs on Android 6.0.1 "Marshmallow".
Release Date: January 2, 2017